What are the coordinates of the midpoint of a segment with endpoints at (8, 25) and (16, 7)?


CLEAR CHECK

(0, 43)


(8, -18)


(12, 16)


(24, 32)

Answers

Answer 1

Answer:

C) (12, 16)

----------------

Use midpoint equation to find each coordinate:

x = (8 + 16)/2x = 12

and

y = (25 + 7)/2y = 16

So the midpoint is (12, 16).


Related Questions

The point (–1, 0.5) lies on the graph of
f –1(x) = 2x. Based on this information, which point lies on the graph of f(x) = log2x?

Answers

The point which would lie on the graph of f(x) = log2x is; (1, 0.301).

Which point would lie on the graph of f(x) = log2x?

Since it follows from the task content that the given point (–1, 0.5) lies on the graph of f –1(x) = 2x.

The subsequent graph of f(x) = log2x would result from taking logarithms in which case, we have the graph passing through points determined as follows;

f(x) = log2^x

f(x) = x log2

Hence, when x = 1;

f(1) = 1log 2

Hence, we have point; (1, 0.301).

Read more on functions;

https://brainly.com/question/875118

#SPJ1

Which of the following is a true proportion of the figure based on the triangle
proportionality theorem?

Answers

Based on the triangle proportionality theorem, the true proportion is h/j=k/i

How to solve for the true proportion

In the diagram that we have here, we have TU to be parallel to QR.

We have following

ST is equal to h, TQ is equal to j, SU is equal to k and UR is equal to i.

This can then be used to form the equation

ST/TQ = SU/UR

When we h/j = k/i

Read more on proportionality here:

https://brainly.com/question/20384391

#SPJ1

Linda is training to be an assistant at the local animal shelter. To become an assistant she needs to complete 48 h of training. Linda keeps a graph of the number of hours of training left to be completed. What is the rate of change of the number of hours remaining with respect to the number of days? Remember to include units.

Answers

The equation between the number of days remaining and number of hours is given as y= -5x+50.

How to illustrate the equation?

Let y be the number of days remaining and x be the no.of hours.

From the graph the slope of the line is given by m.

m=(y2 - y1)/(x2 - x1)

m=(30 - 40)/(4 - 2)

m= -10/2 = -5.

The above slope is in between points 2 and 4. As the line has a constant rate of growth the slope is the same between any points of the line.

Therefore the equation between the no.of days remaining and no.of hours is given by

y=mx +c.

y=-5x+c

Now to find the value of c. This can be determined by substituting the x and y values at a particular instant. For x=0,y=50. Therefore by these values, we get,

50= -5(0)+c

c=50.

Therefore the relation between the number of days remaining and number of hours is given as y= -5x+50.

Learn more about equations on:

https://brainly.com/question/2972832

#SPJ1

Beginning with the graph of f(x) x2, what transformations are needed to form g(x) = 3(x + 2)2 - 1?
O The graph of g(x) is narrower than f(x) and S shifted to the right 2 units and down 1 unit.
O The
graph of g(x) is narrower than f(x) and is shifted to the left 2 units and down 1 unit.
• The graph of g(x) is wider than f(x) and is shifted to the left 2 units and down 1 unit.
• The graph of g(x) is wider than f(x) and is shifted to the right 2 units and down 1 unit.

Answers

Answer: The graph of g(x) is narrower than f(x) and is shifted to the left 2 units and down 1 unit.

Step-by-step explanation:

See attached image.

The function f(x) = x² is transformed and became g(x) = 3(x+2)² -1 has the graph of g(x) is wider than f(x) and is shifted to the left 2 units and down 1 unit.

What are graph transformations ?

By applying suitable graph transformation we can shift, stretch, shrink, a given graph along x and y axis.

According to the given question given a graph f(x) = x² and g(x) is                        3(x+2)² - 1.

Let us break transformations of g(x) one by one.

g(x) = 3f(x) which implies it's amplitude or vertical stretch is increased by a factor of 3.

Now, g(x) = 3(x+2)² implies the graph is shifted towards left by 2 units as x + 2 = 0 is x = -2.

Now, g(x) = 3(x+2)² - 1 implies that the whole graph has been shifted 1 units down along the y axis.

learn more about graph transformations here :

https://brainly.com/question/10059147

#SPJ2

find the value of x

a) 2:5=8:x

Answers

Step-by-step explanation:

solution:

given,

or, 2:5 = 8:x

or, 2/5 = 8/x [ changing into fraction form ]

or, 2x = 40 [ doing cross-multiplication ]

or, x = 20 [ dividing both sides with 2]

Two sides of a triangle have lengths 18m and 23m. Describe the possible length of the thired side

Answers

The possible length of the third side will be values that are less than 41 and greater than 5

Triangular theorem

For three sides to be the sides of a triangle, the sum of any two sides of the triangle must be greater than the third.

Given the two sides of a triangle have lengths 18m and 23m, the sum of the sides is given as:

sum = 18 + 23

Sum = 41

Let the third side be x, such that;

x + 18 >23

23 + x > 18

x >  23 - 18

x > 5

Similarly

x > -5

Hence the possible length of the third side will be values that are less than 41 and greater than 5

Learn more on side of triangle here: https://brainly.com/question/12240062

#SPJ1

A person draws a card from a hat. Each card is one color, with the following probabilities of being drawn: 1/5 for pink, 1/25 for blue, 1/10 for yellow, and 1/15 for black. What is the probability of pulling a blue or yellow card,

Answers

The probability of pulling a blue or yellow card, written as a reduced fraction is 7/50

How to determine the probability of pulling a blue or yellow card, written as a reduced fraction?

From the question, we have the following probabilities:

P(Pink) = 1/5

P(Blue) = 1/25

P(Yellow) = 1/10

P(Black) = 1/15

The probability of pulling a blue or yellow card, written as a reduced fraction is the calculated as:

P(Blue or yellow card) = P(Blue card) + P(Yellow card)

Substitute the known values in the above equation

P(Blue or yellow card) = 1/25 + 1/10

Express 1/25 as 2/50 and 1/10 as 5/10

P(Blue or yellow card) = 2/50 + 5/50

Take the LCM

P(Blue or yellow card) = (2+ 5)/50

Evaluate the sum

P(Blue or yellow card) = 7/50

Hence, the probability of pulling a blue or yellow card, written as a reduced fraction is 7/50

Read more about probability at:

https://brainly.com/question/25870256

#SPJ1

−6 + 3 = −21 pls can uhelp me with this

Answers

Answer:

No Solution

Step-by-step explanation:

1) Simplify -6 - 3 to -3.

-3 = -21

2) Since -3 = -21 is false, there is no solution.

No solution

A random sample of vehicle mileage expectancies has a sample mean of x¯=169,200 miles and sample standard deviation of s=19,400 miles. Use the Empirical Rule to estimate the percentage of vehicle mileage expectancies that are more than 188,600 miles. Round your answer to the nearest whole number (percent).

Answers

The percentage of vehicle mileage expectancies that are more than 188,600 miles is 93%

How to determine the percentage?

The given parameters are:

Mean = 169200

Standard deviation = 19400

x = 188600

Calculate the z value using:

[tex]z = \frac{x - \mu}{\sigma}[/tex]

So, we have:

[tex]z = \frac{188600 - 169200}{19400}[/tex]

Evaluate

z = 1

Using the Empirical Rule, we have:

P(x > 188600) = P(z > 1.5)

From z table of probability, we have:

P(x > 188600) = 0.93319

Express as percentage

P(x > 188600) = 93.319%

Approximate

P(x > 188600) = 93%

Hence, the percentage of vehicle mileage expectancies that are more than 188,600 miles is 93%

Read more about Empirical Rule at:

https://brainly.com/question/10093236

#SPJ1

Q1. A man wants to paint his house in 3 colors. If he can choose 3 colors out of 6 colors, how many
different color settings can he make?
(A) 216 (B) 20 (C) 18 (D) 120

Answers

my best guess is 120

Calculate the distance between the points C = (0,-2) and L= (-4, 1) in the coordinate plane. Give an exact answer. (not a decimal approximation)

Answers

Answer: 5

Step-by-step explanation:

[tex]\sqrt{(-4-0)^2 + (1-(-2))^2}=5[/tex]

A government buys `x`fighter planes at `z` dollars each, and `y` tons of wheat at w dollars each. It spends a total of `B`dollars, where `B=xz+yw`. Write an equation whose solution is the given quantity:



2. The price of a ton of wheat, given that a fighter plane costs 100,000 times as much as a ton of wheat, and that the government bought 20 fighter planes and 15,000 tons of wheat for a total cost of $90 million.

Answers

The equation whose solution is the given quantity is 90,000,000 = 2,000,000w + 15,000w where w = $44.67

Equation

B = xz + yw

Where,

B = Total cost = 90x = number of fighter plane = 20y = tons of wheat = 15,000w = cost of each tons of wheatz = cost of fighter planez = 100,000w

B = xz + yw

90,000,000 = (20 × 100,000w) + (15,000 × w)

90,000,000 = 2,000,000w + 15,000w

90,000,000 = 2,015,000w

w = 90,000,000 / 2,015,000

= 44.6650124069478

Approximately,

w = $44.67

Learn more about equation:

https://brainly.com/question/2972832

#SPJ1

2) (x+3)
2) Correct the error:
There is an error in the students' work shown below:
Question: Simplify (x-3)(x-7)
Solution: (x-3)(x-7)
x-x-3(x)-7(x) - 21
x²-10x-21
What is the error? Explain how to solve the problem.

Answers

The expression x²-10x-21 is wrong since the product of two negative signs is equal to positive.

Simplifying  factors

Quadratic equations are equations that has a leading degree of 2. The standard quadratic equation is given as;

f(x) = ax^2+bx+c

Given the product of the expression below;

f(x) = (x-3)(x-7)

Expand

f(x) = x(x) - 7x - 3x -3(-7)

f(x) = x^2 - 7x - 3x + 21

f(x) = x^2 - 10x + 21

Hence the expression x²-10x-21 is wrong since the product of two negative signs is equal to positive.

Learn more on factoring here: https://brainly.com/question/25829061

#SPJ1

Can anyone help me with this question?:)

Answers

Answer:

ΔABC ≅ ΔEDF

Step-by-step explanation:

Triangle ABC is congruent to triangle EDF because they're the same size.

[tex] \qquad \qquad \bf \huge\star \: \: \large{ \underline{Answer} } \huge \: \: \star[/tex]

[tex]\textsf{ \underline{\underline{Steps to solve the problem} }:}[/tex]

[tex] \sf\triangle ABC \cong \triangle DEF[/tex]

For checking congruency, we need to follow a proper order when choosing the triangle. because each triangle name is unique in itself.

So, According to Triangle ABC, we need to find the triangle with first two letters That resembles AB, that is :

AB = DE

and next should be :

BC = EF

[tex] \qquad \large \sf {Conclusion} : [/tex]

so, now we got the sense for naming, therefore the answer will be :

[tex] \sf\triangle ABC \cong \triangle DEF[/tex]

A couple deposits $20,000 into an account earning 5% annual interest for 30 years. Calculate the future value of the investment if the interest is compounded monthly. Round your answer to the nearest cent.

Answers

The future value of the investment if the interest is compounded monthly is $89,354.89.

What is the future value of the investment?

Given that;

Principal P = $20,000Annual interest rate r = 5% = 5/100 = 0.05Time t = 30 yearsCompound monthly = 12Future value = A = ?

Using the compound interest formula;

A = P( 1 + r/n )^(nt)

We plug in our values.

A = 20000( 1 + 0.05/12 )^(12 × 30)

A = 20000( 1 + 0.0041666666666667)^(360)

A = 20000( 1.0041666666666667)^(360)

A = 20000( 4.46774965 )

A = 89354.89

Therefore, the future value of the investment if the interest is compounded monthly is $89,354.89.

Learn more about compound interest here: https://brainly.com/question/21270833

#SPJ1

A group of college students are going to a lake house for the weekend and plan on renting small cars and large cars to make the trip. Each small car can hold 5 people and each large car can hold 7 people. A total of 10 cars were rented which can hold 66 people altogether. Write a system of equations that could be used to determine the number of small cars rented and the number of large cars rented. Define the variables that you use to write the system.

Answers

The system of equations that could be used to determine the number of small cars rented and the number of large cars rented is;

x + y = 10

x + y = 105x + 7y = 66

Simultaneous equation

Small car = 5 peopleLarge car = 7 peopleTotal cars = 10Total number of people = 66

Let

Number of small cars rented = x

Number of large cars rented = y

x + y = 10

x + y = 105x + 7y = 66

Learn more about simultaneous equation:

https://brainly.com/question/16863577

#SPJ1

The function f(x)=−4x4+3x3−2x2−x+5 is/has A. order 2 rotational symmetry about the origin
B. neither symmetry about the y-axis nor has order 2 rotational symmetry about the origin
C. even
D. odd

Answers

The answer choice which describes the function is; Choice B; neither symmetry about the y-axis nor has order 2 rotational symmetry about the origin.

What is rotational symmetry?

Rotational symmetry, otherwise termed radial symmetry, is the characteristic of a shape when it looks the same after some rotation by a partial turn. On this note, since the function represents a quartic graph, it follows that the function has neither symmetry about the y-axis nor has order 2 rotational symmetry about the origin.

Therefore, the function f(x) = −4x⁴ + 3x³ − 2x² − x + 5 is neither symmetry about the y-axis nor has order 2 rotational symmetry about the origin.

Read more on rotational symmetry;

https://brainly.com/question/15178808

#SPJ1

the function f(t) = 5 cos(pi/4*t) + 11 represents the tide in dark sea. it has a maximum of 16 feet when time (t) is 0 and a minimum of 6 feet. the sea repeats this cycle every 8 hours. after six hours, how high is the tide?

Answers

The height of the tide after eight hours is 16 feet.

How to illustrate the function?

From the information given, the function is given as 5cos (π/4)t + 11.

In this case, the time is given as eight hours. This will be:

f(8) = 5 × cos (π/4) × 8 + 11

f(8) = 5 × cos(2π) + 11

= (5 × 0.999) + 11

= 16 feet

The height is 16 feet.

Learn more about functions on:

brainly.com/question/5957029

#SPJ1

QUICK I need help on what the answer is and an explanation would be much appreciated too thank you

Answers

The nonreal solutions to the polynomial equation are: (2 + i√11, 2 - i√11).

How to determine the nonreal solutions?

By critically observing the graph given, we can logically deduce that the real solutions of the polynomial are -1 and 4. This ultimately implies that, the given polynomial expression can be evaluated as follows:

(x + 1)(x - 4) = x² - 3x - 4.

x⁴ - 7x³ + 23x² - 29x - 60 = x² - 3x - 4.

Also, the nonreal solutions can be determined by dividing the polynomial expression by the real solutions as follows:

Nonreal solutions = (x⁴ - 7x³ + 23x² - 29x - 60)/(x² - 3x - 4)

Nonreal solutions = (2 + i√11, 2 - i√11).

Read more on polynomials here: brainly.com/question/19571593

#SPJ1

PLEASE HELP! And thank you so much! I will mark you brainliest. I just need an urgent response! Thank you for your time

Answers

Answer:

A)

x + y = 80

y = x + 20

B) x = 30 minutes

C) No. If Pam dances for 60 minutes, and dances for 20 minutes longer than she does math, then she does math for 40 minutes. This means she spends 100 minutes total. 100 minutes is not 80 minutes, thus this is not possible.

Step-by-step explanation:

A)

x + y = 80

y = x + 20

B) x = 30 minutes

Replacing y with x + 20 in the first equation ->

x + x + 20 = 80

2x + 20 = 80

2x = 60

x = 30

C) No. If Pam dances for 60 minutes, and dances for 20 minutes longer than she does math, then she does math for 40 minutes. This means she spends 100 minutes total. 100 minutes is not 80 minutes, thus this is not possible.

Find DE
3x - 28
3x - 30
D
G
E
F
33

Answers

Answer:

11

Step-by-step explanation:

(3x-28) + (3x-30) + x = 33

7x - 58 = 33

7x = 91

x = 13

DE = 3x - 28 = 3*13 - 28 = 11

Molly wants to buy a dress that costs $20. She has a coupon for 40% off, and there is a 10% sales tax. how much will she pay all together

1. after using the coupon what is the sale price of the dress Show Your Work
2.how much is th 10% tax on the sale price Explain how you found your answer

Answers

Answer:

$13.50

Step-by-step explanation:

If I am taking off 40%, that means that the dress now cost 60% of the original cost.  .6 x 20 is 12.

You could also calculate the 20% off and subtract that from the original cost.  .4 x 20 =8.  Now 20 - 8 is also 12.

Now, we have to calculate the tax.  10% of 12 is .1 x 12 or $1.20.  We add the tax to the 12 to get 13.50.

Thomas took 3h to paint a room. Brian could paint the same room in 6h. How long would it take for both of them to finish painting the same room together?


please help !! no algebra please​

Answers

Answer:

2 hours

Step-by-step explanation:

If Thomas can paint 1/3 = 2/6 of the room in a hour and Brian can paint 1/6 of the room in an hour. Which means in an hour they can collectively paint 3/6 = 1/2 of the room. Now you need to find how long it would take then to paint 2/2 of the room. Knowing that 1/2+1/2 = 2/2, it would take them 2 hours to paint the room together

Use the drawing tool(s) to form the correct answer on the provided graph.

Graph the solution to this system of inequalities in the coordinate plane.

3y 2x+122x + y ≤5

Answers

The plotting of the inequalities was done using geogebra online graphing calculator. The graph is attached.

What are inequalities?

Inequalities are the mathematical expressions in which both sides are not equal. It should be noted that in inequality, unlike in equations, we compare two values.

The equal sign in between is replaced by less than (or less than or equal to), greater than (or greater than or equal to), or not equal to sign. Inequality is an expression used to show the nonequal comparison of numbers and variables.

Given the system of inequalities:

3y > 2x + 12

3y - 2x > 12   (1)

2x + y < -5    (2)

Plotting the inequalities using GeoGebra online graphing calculator. The graph is attached

Learn more on inequalities on:

brainly.com/question/11613554

#SPJ1

What is the length of the apothem of the regular pentagon shown below? Round to one decimal place

Answers

Answer:

A

Step-by-step explanation:

Draw a diagonal line connecting the centre to a vertex at the bottom. This makes a triangle. It is a regular pentagon so the base of that triangle is 7.6 / 2, which is 3.8. You also know that the angle from the apothem to the base is 90 degrees. You also know that you could split the centre angle into 5 triangles. 360 / 5 = 72 and we have half of it so it is 36 degrees.

Let's see what we have so far:

The base of the triangle is 3.8

The angle at the bottom is 90

The angle at the top is 36

We now have the tan and the opposite and we need the adjacent so rearrange for adjacent.

This gives you adjacent = opposite / tan(angle)

adjacent = 3.8 / tan(36)

adjacent = 5.2m

Drag a statement or reason to each blank in the table to complete the proof that <1 is congruent to <7.

Answers

Step-by-step explanation:

<1 congruent to <5.

<5 congruent to <7.

<1 congruent to <7.

Answer:

don't know but i need thee points

Step-by-step explanation:

A matrix A has x rows and x+5 columns. B has y rows and 11−y columns. Both AB and BA exist. Find x and y.

Answers

Answer:

  x = 3

  y = 8

Step-by-step explanation:

A matrix product exists if and only if the number of columns in the left matrix is equal to the number of rows in the right matrix.

Setup

For AB to exist, we must have ...

  columns of A = rows of B

  x +5 = y

For BA to exist, we must have ...

  columns of B = rows of A

  11 -y = x

Solution

Using the second equation to substitute for x in the first equation, we have ...

  (11 -y) +5 = y

  16 = 2y

  8 = y

Then the value of x is ...

  11 -8 = x = 3

The values of x and y are ...

x = 3y = 8

__

Additional comment

The dimensions are A = 3×8; B = 8×3.

A linear function always increases

-true

-false

Answers

Answer: False

Step-by-step explanation:

If the function has a negative slope, then it will decrease.

The equation T^2= A^3 shows the relationship between a planets orbital period, T, and the planets mean distance from the sun, A, in astronomical units, AU. if the orbital period of planet Y is twice the orbital period of planet x, by what factor is the mean distance increased?

Answers

The mean distance increased by a factor of 2^(²/₃)

How to find the factor of increase?

The given equation for the relationship between a planet's orbital period, T and the planet's mean distance from the sun, A is;

T² = A³.

Let the orbital period of planet X = T(X).

Let the orbital period of planet Y = T(Y).

Let the mean distance of planet X from the sun = A(X).

Let the mean distance of planet Y = A(Y).

Thus;

A(Y) = 2A(X)

Therefore;

[T(Y)]² = [A(Y)]³ = [2A(X)]^3

However, [T(X)]² = [A(X)]³

Thus;

[T(Y)]² = 2³[T(X)]² * [T(Y)]²/[T(X)]² = 2³T(Y)/T(X) = 2^(³/₂)

That's for orbital period but the mean distance will increase by 2^(²/₃)

Thus we conclude that, the mean distance increased by a factor of 2^(²/₃)

Read more about factor of increase at; https://brainly.com/question/1638294

#SPJ1

Answer:

2 Superscript three-halves

Step-by-step explanation:

Edge

PLEASE HELP!!!!
Cooling towers are used to remove or expel heat from a process. A cooling tower's walls are modeled by x squared over 400 minus quantity y minus 110 end quantity squared over 2304 equals 1 comma where the measurements are in meters. What is the width of the cooling tower at the base of the structure? Round your answer to the nearest whole number.

100 meters
50 meters
48 meters
40 meters

Answers

Answer:

  (a)  100 meters

Step-by-step explanation:

You want the width at the base of a cooling tower whose walls are modeled by the equation (x/20)² -((y-110)/48)² = 1.

Base

The width at the base will be the difference in the values of x when y=0.

  (x/20)² -((0 -110)/48)² = 1

  (x/20)² = 1 +3025/576

  x = ±20/24√3601 ≈ ±50.01

The width will be 50.01 -(-50.01) ≈ 100 meters.

<95141404393>

Other Questions
You are boiling water to cook some noodles. You notice bubbles forming on the bottom of the pot. Your brother thinks it is a chemical change. Is he correct?Yes. The bubbles contain hydrogen and oxygen that separated from the water.Yes. The bubbles are now filled with air.No. The water changes into carbon dioxide.No. It is a physical change when water is heated and is converted into water vapor. How much of the moon's bright side can you see during a new moon? a. 0%b. 20% c. 40%d. 60% What is the volume of a gas at 20cIf its orginal volume at 60Cis 300 cm? The spinner below is divided into five equal-sized sectors. What is the probability that the spinner will stop on a number greater than 3? ill make you brainiest What information do the details in this passage give the reader about the plot?They show a characters description.They show a characters conflict.They show a characters change.They show a characters turning point. Brady is conducting an experiment using a spinner with four different colors: red, orange, blue, and green. He spun the spinner 40 times and recorded the following data.Based on the data in the table, if Brady spins the spinner 240 times, he predicts the spinner will land on red roughly A. 48, B. 24, C. 12, D. 36 times. He also predicts the spinner will land on green roughly A. 108, B. 72, C. 48, D. 36 more times than it will land on red. help Ill give you brainliest 8(8p+8)=640 solve Answer ASAP please A finales de 2017, 3.766.000 espaoles no tenian trabajo Si el numerode desocupacios disminuy un 13% durante el ao siguiente , cuantos desocupados habia en Espaa a finales de 2018? Adrianna is two years older than Fernando, while Lucy is triple Fernando's age. If the sum of their ages is eighty-two, how old is Adrianna?HELPPPP MEEEEE!!!!!! The angle of depression from a window 10 m above the ground to a coin on the ground is15. Find the distance of the coin from the base of the building. Probably of Carl solving the 10 problems if there's 20 to study and he knows 15 and ten of the 20 are on the test. File Is Attached To The Question Refer to the "Discover Shakespeare" content. What is the author's viewpoint about Shakespeare?Shakespeare's works may not be original since they were published by his friends.Shakespeare is most remembered for his skills in acting. Shakespeare owes his success in the theater, in part, to Queen Elizabeth I .Shakespeare had little time for family due to his work in the theater. Read Patrick Henry's speech, "Give Me Liberty or Give Me Death!" and analyze it.What is the speakers viewpoint? What is his claim?What reasons does the speaker provide to support his viewpoint or claim?How valid are the speakers reasons for his claim? Use evidence from the text to support your answer.What evidence does the speaker provide to support his reasons?Is the speakers evidence relevant and sufficient? Use evidence from the text to support your answer.Does the speaker use fallacious reasoning or logical fallacies? Use evidence from the text to support your answers.What counterclaims or alternate claims does the speaker address, and how does he respond to them? Does someone know this? The transverse plane does not divide the body into two ___ halves.Answer Choices:A. DistalB. Perpendicular C. Symmetrical If you dont know it, its fine :) An economic model which the laws of supply and demand determine what is produced and consumed and at what cost which are examples of puns HELPPPPP HELLPPPPPP Plsss How did railroads promote economic expansion in the U.S.