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2 years ago

Please Solve for the value of k.

Mathematics

1 answer:

alukav5142 [94]2 years ago

8 0

Answer:

k = 13

Step-by-step explanation:

The sum of the angles is 180 since they form a straight line

4k-7 + 90 + 3k+6 = 180

Combine like terms

7k+89=180

Subtract 89 from each side

7k+89-89 = 180-89

7k =91

Divide each side by 7

7k/7 = 91/7

k = 13

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XVerify the identity. (7 points) cos 4u = cos22u - sin22u

Alexandra [31]

Answer:

cos 4u = co^s2 2u - sin^2 2u

Step-by-step explanation:

cos 4u = co^s2 2u - sin^2 2u

Let 4u = 2x

cos 2x = cos^2 x - sin^ 2 x

cos (x+x) = cos^2 x - sin^ 2 x

Using cos(x+y) = cos(x)cos(y) -sin(x)sin(y)

cos(x) cos(x)- sin(x) sin (x)= cos^2 x - sin^ 2 x

cos^2 (x) -sin^2 (x) =cos^2 x - sin^ 2 x

Since this is true

cos 2x = cos^2 x - sin^ 2 x

This is true

Substituting 4u back for 2x

cos 4u = co^s2 2u - sin^2 2u

This is true

5 0

2 years ago

Please help me solve question 2

sergiy2304 [10]

Answer:

solution: ( 3 , 6 )

$\sf y =6$

$\sf x =3$

Step-by-step explanation:

$\sf y = \frac{2}{3} x+4$

$\sf 2x+3y = 24$

make y the subject in equation 2:

$\sf 2x+3y = 24$

$\sf 3y = 24-2x$

$\sf y = \frac{24-2x}{3}$

insert this in equation 1:

$\sf \frac{24-2x}{3} =\frac{2}{3} x+4$

$\sf \sf \frac{24-2x}{3} =\frac{2x+12}{3}$

$\sf (24-2x) = (2x+12)$

$\sf -2x-2x=12-24$

$\sf -4x=-12$

$\sf x =3$

solve for y:

$\sf y = \frac{24-2x}{3}$

$\sf y = \frac{24-2(3)}{3}$

$\sf y =6$

8 0

2 years ago

Read 2 more answers

What is the fraction in decimal form? 13/20

Marta_Voda [28]

13/20 = 65/100

65/100 = 0.65

hope this helps

7 0

2 years ago

Read 2 more answers

PLEASE HELP FAST!! <br>28. Find the value of x In the figure below. Show your work.

IceJOKER [234]

Answer:

Step-by-step explanation:

its 62

4 0

1 year ago

How many weeks of data must be randomly sampled to estimate the mean weekly sales of a new line of athletic footwear? We want 98

Irina18 [472]

Answer:

$n=(\frac{2.33(1400)}{400})^2 =66.50 \approx 67$

So the answer for this case would be n=67 rounded up

Step-by-step explanation:

Information given

$\bar X$ represent the sample mean for the sample

$\mu$ population mean

$\sigma=1400$ represent the sample standard deviation

n represent the sample size

Solution to the problem

The margin of error is given by this formula:

$ME=z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (a)

And on this case we have that ME =400 and we are interested in order to find the value of n, if we solve n from equation (a) we got:

$n=(\frac{z_{\alpha/2} \sigma}{ME})^2$ (b)

The critical value for 98% of confidence interval now can be founded using the normal distribution. And the critical value would be $z_{\alpha/2}=2.33$ , replacing into formula (b) we got:

$n=(\frac{2.33(1400)}{400})^2 =66.50 \approx 67$

So the answer for this case would be n=67 rounded up

8 0

2 years ago