posted by Melanie on .
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! :)
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.
Post your answers for confirmation if you wish.
For 1, I got G and for the second one I got B. are they correct?
G is correct for 1.
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.
Ummm is it C?
You do not seem very sure about it. Can you demonstrate why it is, or it is not C?
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 :)