SOLUTION: Here is the question. Find k if the lines 3x-y=9 and kx+3y=5 are perpendicular. I arranged both equations to equal y; y=3x-9 and y=(5-kx)/3, but I don't know where to go from there

Question 211350: Here is the question. Find k if the lines 3x-y=9 and kx+3y=5 are perpendicular. I arranged both equations to equal y; y=3x-9 and y=(5-kx)/3, but I don't know where to go from there
Answer by checkley77(12844) (Show Source): You can put this solution on YOUR website!
3x-y=9
-y=-3x+9
y=3x+9 ( red line)this line has a slope of 3.
Therefore all perpendicular lines will have a slope=-1/3
kx+3y=5
3y=-kx+5
y=-kx/3+5/3
[-k/3=-1/3]
k=1 ans.
y=-x/3+5/3 (green line)
(graph 200x200 pixels, x from -10 to 10, y from -10 to 10, of TWO functions 3x +9 and -x/3 +5/3).
RELATED QUESTIONS
I need help with this question, I'll give the exact question. Question: Given that... (answered by stanbon)

If 3x+ky=7 and y=3-4x are two equations of two different lines find �k� if the lines are... (answered by josgarithmetic,ikleyn)

Find the value of k if the lines 2x-3y=5 and 6x-(k+1)y =1 are... (answered by josgarithmetic)

Find k if he following system of equations has a unique solution? 2x+(k-1)y=6... (answered by Edwin McCravy)

If y varies dirctly as x, and x = 9 when y = 15, find y when x = 33. I think the formula... (answered by pmatei)

If the lines mx + 3y =1 and 3x + (m− 4) y = 5 are perpendicular. Find... (answered by fractalier)

Hi, I'm Michele and I could really use someones help on my problem. I will be greatful... (answered by stanbon)

write the equations of two lines whose graphs are perpendicular to y=-1/3x-9 (answered by ewatrrr)

for each pair of equations, determine if the lines are parallel, perpendicular, or... (answered by Earlsdon,josmiceli)