How do i find the perpendicularity of x+y=7

Question

How do i find this perpendicularity 

Answer 1

y = -x + 7

 

Perpendicular lines have opposite, reciprocal slopes. With -x, the slope is -1 = -1/1, so the perpendicular slope is 1/1 = 1.

 

If you need an equation, since the y-intercept of our given equation is 7, one point on the line is (0,7).

 

y - 7 = 1(x - 0)

y - 7 = x

x - y = -7