Question

Do the equations 3+y=20 and x-3y=7 represent two perpendicular lines? Why or Why not?

Answer 1

If it's 3x+y=20 and x-3y=7, then they are two perpendicular lines

Answer 2

but how?

Answer 3

Solve for y in each case


3x+y=20


y=-3x+20


Slope here is -3


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x-3y=7


-3y=-x+7


y = 1/3x-7/3


Slope here is 1/3


Since the two slopes are negative reciprocals of one another, the two lines are perpendicular to each other.