Write the product (4 + i)(4 − i) in the form a + bi. A. 16 − i B. 16 − i2 C. 17 D. 8

Answer:

(1-cos2A) /(1+cos2A) =tan²A

Proof:

We know that,

cos(A+B) =cosA.cosB-sinA.sinB

=>cos2A=cos(A+A)

=>cos2A=cosA.cosA - sinA.sinA

=>cos2A=cos²A-sin²A

=>cos2A=(cos²A-sin²A)/(cos²A+sin²A

Since {cos²A+sin²A=1}

Divide the numerator & the denominator by (cos²A) to get,

cos2A = {(cos²A-sin²A) ÷cos²A} / {(cos²A+sin²A) ÷cos²A}

cos2A ={(1-tan²A)/(1+tan²A)}

Then,

1-cos2A = 1-[{(1–tan²A)/(1+tan²A)}]

1-cos2A =(1+tan²A-1+tan²A)/(1+tan²A)

1-cos2A=(2tan²A)/(1+tan²A)

And now.......

1+cos2A=1+[{(1-tan²A)/(1+tan²A)}]

1+cos2A={1+tan²A+1-tan²A}/{1+tan²A}

1+cos2A=2/(1+tan²A)

So now,

(1-cos2A)/(1+cos2A)= {2tan²A/(1+tan²A)}÷{2/(1+tan²A)}

={(2tan²A)(1+tan²A)}÷{2(1+tan²A)}

=tan²A

Step-by-step explanation:

make me as brain liest

Answer:

22.5

Step-by-step explanation:

Answer:

2.5

Step-by-step explanation:

Cross multiply:

9 * 5 = x * 18

Simplifying

9 * 5 = x * 18

Multiply 9 * 5

45 = x * 18

Reorder the terms for easier multiplication:

45 = 18x

Solving

45 = 18x

Solving for variable 'x'.

Move all terms containing x to the left, all other terms to the right.

Add '-18x' to each side of the equation.

45 + -18x = 18x + -18x

Combine like terms: 18x + -18x = 0

45 + -18x = 0

Add '-45' to each side of the equation.

45 + -45 + -18x = 0 + -45

Combine like terms: 45 + -45 = 0

0 + -18x = 0 + -45

-18x = 0 + -45

Combine like terms: 0 + -45 = -45

-18x = -45

Divide each side by '-18'.

x = 2.5

Simplifying

x = 2.5

Answer:

C/8    -k= y

Step-by-step explanation:

C=8(y + k)

Divide each side by 8

C/8 = y+k

Subtract k from each side

C/8  -k = y+k-k

C/8    -k= y

Answer: y  =  C /8 −  k

Step-by-step explanation:

Answer:

Step-by-step explanation:

Let Lucas final grade be x

All Lucas grade will be 75, 78, 82, and 84 and x.

Average score = 95

Since we are not told what to look for, we can find the Lucas final grade.

Using the formula for calculating mean (average)

Mean = Sum of the score/total test taken

95 = 75+78+82+84+x/5

95 = 319+x/5

Cross multiply

95×5 = 319+x

475 = 319+x

x = 475-319

x = 156

Lucas final grade is 156

One sixth of Lucas final grade = 1/6 × 156 = 26

Answer:

C

Step-by-step explanation:

4a+10=180

4a=170

a=42.5

42.5*2=85

Answer: C. 85.0 degrees

Step-by-step explanation: First you find a using the equation they gave you. A=42.5. Then you plug it into the measures of the angles. But just by looking at the angles you can tell 2a would be the largest so you just plug a in there and you get your answer!

Answer:

b/c it's an even function you know that  f(x) = f(-x) too  so whether you put in a positive X or a negative X you get the same answer  so you know.. that (-6,9) is also on the graph of this function

Step-by-step explanation:

Given that the function is even and we know that (6, 9) is on its graph, we know that (-6, 9) must also be on the graph.

A function f(x) is even if:

f(x) = f(-x)

Now, we know that the point (6, 9) is on the graph of our function, this means that:

f(6) = 9

And because our function is even, we must have:

f(6) = f(-6) = 9

Then the point (-6, 9) must also be on the graph of the function.

If you want to learn more about even functions, you can read:

https://brainly.com/question/5719984

Answer:

For a rectangle of length L and width W, the area is:

A = L*W

In this case, we start with:

L = 14ft

W = 10ft

Then the initial area is:

A = 14ft*10ft = 140ft^2

a) Now she wants to increase the same amount in each measure, then the new measures will be:

L = 14ft + x

W = 10ft + x

Now we want this new area to be twice the one that we got before, then the equation will be:

(14ft + x)*(10ft + x) = 2*140ft^2 = 280ft^2.

b) Let's solve the equation:

(14ft + x)*(10ft + x) = 280ft^2

First lets distribute the multiplication:

140ft + x*10ft + 14ft*x + x^2 = 280ft

Now let's group terms with the same power of x.

x^2 + (10ft + 14ft)*x + 140ft - 280ft = 0.

x^2 + 24ft*x  - 140ft = 0.

Now we need to solve this quadratic equation, here we must use the Bhaskara equation for quadratic equations, and we will get two solutions for x.

[tex]x = \frac{-24ft +- \sqrt{(24ft)^2 - 4*140ft*1} }{2*1} = \frac{-24ft +- 33.7ft}{2}[/tex]

Then the two solutions are:

x = (-24ft - 33.7ft)/2 = -28.9 ft

This solution is negative, so it does not make sense and we can discard it.

x = (-24ft + 33.7ft)/2 = 4.85ft

This is positive, so we can use this.

Now we can find the new length and width:

L =  14ft + 4.85ft = 18.85ft

W = 10ft + 4.85ft = 14.85ft

Answer:

Answer: -2x+12

Step-by-step explanation:

So, it says the expression equals 2A + B. That means you need to multiply the equation for A by 2 and then add the equation of B to it. The question is asking you to write it in standard form. It would look like this:

2(-2x+8) + 2x-4

-4x+16+2x-4

-2x+12

Answer:

$26

Step-by-step explanation:

Step one:

given data

cost of limo=$20

cost per mile= 12cent to dollar = $0.12

Step two:

let the total cost be y

and the number of mile be x

the model for the situation is

y=mx+c

Step three:

given x=50mile

y=0.12(50)+20

y=6+20

y=26

$26

Matthew will spend $26 to get to the hospital

Answer:

y = (-1/4)x + 1 so that the y-intercept is 1

Step-by-step explanation:

The slope is (-1 - 2)/[8 - (-4)] = -3/12 = -(1/4)

(-1/4) = (y - 2)/(x + 4) => -x - 4 = 4y - 8

-x + 4 = 4y

y = (-1/4)x + 1 so that the y-intercept is 1

Answer:

V=72x³y³

Step-by-step explanation:

The formula to apply is;

V= l * w * h where

V= volume in units cubed.

l= length = 3xy

w=width = 4xy

h= height = 6xy

Substitute values in the formula as;

V= l*w*h

V=3xy * 4xy * 6xy ----find product for the numbers {3*4*6=72} then multiply by the product for x's {x*x*x =x³} that of y's {y*y*y=y³}

V= 72*x³*y³

V= 72x³y³  --------where xy are the units used.

Answer:

1.092

Step-by-step explanation:

Answer:

yes they are equivalent

Answer:

Number of possibilities

1) 91 members that contribute 1 dime each ($0.10)

2) 13 members that contribute 7 dimes each ($0.10 × 7 = $0.70)

3) 70 members that contribute 13 dimes each ($0.10 × 13 = $0.13)

Step-by-step explanation:

A dime = $0.10 in dollars

We are told that:

The total amount contributed = $9.10 for the party after their practice.

Each member contributed the same amount of money in dimes only.

Let the number of members be represented as: x

Number of possibilities

We find the factors of $9.1

= 1, 0.7, 0.13, 9.1

= 1 × 9.1

= 0.7 × 13

= 0.13 × 70

Hence:

1) $0.10 × x = $9.10

x = $9.10/$0.10

x = 91

Therefore, from the calculation above, there are 91 members and each of them contributed the same amount which was 1 dime ($0.10).

2)

7($0.10 )× x = $9.10

x = $9.10/$0.70

x = 13

Therefore, from the calculation above, there are 13 members that contribute 7 dimes each ($0.10 × 7 = $0.70)

3) 13($0.10) × x = $9.10

x = $9.10/$0.13

x = 70

Therefore, from the calculation above, there are 70 members that contribute 13 dimes each ($0.10 × 13 = $0.13)

Answer:

The same thing would happen over and over again.

Answer:

2n - 12 + 4

Step-by-step explanation:

Distribute 2 across the n+6, get 2 x n and get 2n, and 2 x -6 = -12

u need this m8, good day

Answer:

6:1:3

Step-by-step explanation:

Answer:

So I believe you are supposed to find the common denominator between the two so we know that 2 times 2 is 4 and 3 times 3 is nine, and when you multiply 2 and three you get 6. I believe the answer is (6).

Step-by-step explanation: A=6

Answer:

Step-by-step explanation:

Refer the attached picture for complete question

a) V(x)=x(11-2x)(17-2x)

B(x)=140

Side and volume cannot be negative

So, x> 0

11-2x>0   and 17-2x>0

[tex]x<\frac{11}{2}[/tex] and [tex]x< \frac{17}{2}[/tex]

Domain for V(x) :[tex]0<x<\frac{11}{2}[/tex]

b)For finding the greatest Volume

[tex]\frac{dV}{dx}=0[/tex]

[tex]V(x)=x(11-2x)(17-2x)=4x^3-56x^2+187x[/tex]

[tex]\frac{dV}{dx}=12x^2-112x+187=0\\x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}\\x=\frac{112\pm\sqrt{(112)^2-4(12)(187)}}{2(12)}[/tex]

x=7.155 , 2.177

Consider the graph

So, Volume at 7.155 is negative

Thus x≈2 gives the greatest volume

c)

Consider the graph .

It is increasing from [tex]-1 \leq x \leq 2[/tex] and [tex]x \geq 7[/tex]

So, Graph increasing interval is [-1,2] ∪[7,∞)

d)

At the point of intersection, both graph has the same value .

Answer:

B: distinct parallel lines

Step-by-step explanation:

Answer:

90g strawberry jelly, 6 sponge fingers, 315ml custard and 45g tinned fruit

Step-by-step explanation:

just divide everything by 4 to see the value for one and then multiply that value by three!

Answer:

square root of 16

Step-by-step explanation:

the square root of 16 is 4 and 4 times .5 equals 2

See attachment for math work and answer.

Answer:

B

Step-by-step explanation:

We know that it costs 37 cents to mail a letter that weighs 1 oz or less. This would mean that for x ≤ 1, P(x) should equal 37. Already, we can eliminate A and D.

We also know that it costs an additional 26 cents for at most another ounce added to the original 1 ounce. This means that for 1 < x ≤ 2, P(x) = 26 + 37 = 63. This is shown by B.

Thus, the answer is B.

~ an aesthetics lover

Answer:

10

Step-by-step explanation:

10y+15=7y+45

10y-7y=45-15

3y=30

y=10

hope it helps you!

Answer:

A

Step-by-step explanation:

Hope this helps

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Answer: A

Step-by-step explanation: