3y=x-3 y=1/3x-1 Perpendicular slope: -3 y=-3x+b Plug in the coordinates in the equation: -9=-3(5)+b -9=-15+b 4=b Equation: y=-3x+4 Also, when finding the perpendicular slope you take the reciprocal of the original slope and make it negative if it is positive and make it positive if it’s negative.
