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3 years ago

PLEASE HELP!! WILL GIVE BRAINIEST!!! Please solve #7 and #8.

Mathematics

2 answers:

lawyer [7]3 years ago

8 0

7)
slope = (1+3)/(-1+10) = 4/9

y = mx + b
1 = 4/9(-1) + b
b = 1 + 4/9
b = 13/9
equation
y = 4/9x + 13/9

answer is D.y = 4/9x + 13/9

8)
y = 3x - 3
perpendicular so slope = -1/3

passing thru (-7, 9)
equation
y - 9 = -1/3(x +7)

answer is D. y - 9 = -1/3(x +7)

sukhopar [10]3 years ago

3 0

The answer to 7 is:y = (4/9)x + (13/9).
The answer to 8 is B, I think.

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Step-by-step explanation:

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So, our adjacent side is 1, our opposite side is 2√2, and our hypotenuse is 3.

From the above information, substitute in appropriate values. And since <em>x</em> is in QII, cosine and tangent will be negative while sine will be positive. Hence:

<h2> $\displaystyle \tan(2x)=\frac{2(2\sqrt{2}/3)(-1/3)}{(-1/3)^2-(2\sqrt{2}/3)^2}$ </h2>

Simplify:

$\displaystyle \tan(2x)=\frac{-4\sqrt{2}/9}{(1/9)-(8/9)}$

Evaluate:

$\displaystyle \tan(2x)=\frac{-4\sqrt{2}/9}{-7/9} = \frac{4\sqrt{2}}{7}$

The final answer is positive, so we can eliminate A and B.

We can simplify D to:

$\displaystyle \frac{2\sqrt{8}}{7}=\frac{2(2\sqrt{2}}{7}=\frac{4\sqrt{2}}{7}$

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