# Math

posted by .

I need help with two problems. Just want to make sure that the answers I put are correct.

1) Which of the following is an equation of a vertical line?
F. 4x + 5y = 0
G. -4 = 16x
H. 3y = -9
I. 4x + 5y = -1

2) Which equation is the equation of a line that passes through (-10, 3) and is perpendicular to y = 5x - 7?
A. y = 5x + 53
B. y = - 1/5x - 7
C. y = - 1/5x + 1
D. y = 1/5x + 5

It would also be greatly appreciated if you told me how you got your answer. Thanks! :)

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Hints:
1. The equation of a vertical line has the y-term absent, since it is not possible to calculate y for a given x.

2. The slope of L: y=5x-7 has a slope of 5.
The slope of a line perpendicular to L has a slope m such that 5*m=-1, or m=-1/5.
Also, if the line L1 passes through the point P(-10,3), then by substituting x=-10 and solving for y, we should get y=3.

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For 1, I got G and for the second one I got B. are they correct?

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G is correct for 1.

For 2,
if I substitute -10 in y = - 1/5x - 7 ,
I get y=(-1/5)*(-10)-7=2-7=-5, we're looking for 3.
Give it another try. You're close.

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Ummm is it C?

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You do not seem very sure about it. Can you demonstrate why it is, or it is not C?

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I'm sure about it now :) Thank you for your help. I know it is C because once I put in the x and y axis into the equation, I multiplied 1/5 with -10 then added one and the result was three that's how I knew it was C :)