Question 216329
y=4/5x-9 (red line) with a slope=4/5
A perpendicular line has a slope=-5/4
and passing through (8,-13)
-13=-5/4*8+b
-13=-40/4+b
-13=-10+b
b=-13+10
b=-3 the y intercept.
y=-5x/4+3 (green line)
{{{ graph( 300, 300, -10, 10, -10, 10, 4x/5 -9, -5x/4 -3) }}} (graph 300x300 pixels, x from -10 to 10, y from -10 to 10, of TWO functions 4x/5 -9 and -5x/4 -3).