a -5x-4y = 6, solve for y, then the coefficient of the x term is the slope
4y =-5x -6
y =-5x/4 -6/4 5/4 is the slope and the slope of any parallel line the negative inverse -4/5 is the slope of any perpendicular line
y=5x/4 + b, solve for b by plugging in the point (7, -5)
-5 = 5(7)/4 + b
b =-5 -35/4 = -55/4
y =5x/4 -55/4 is the parallel line through the given point
y=-4x/5 + b, solve for b by plugging in the point (7,-5)
-5 = -4(7)/5 + b
b =-5 +28/5 = 3/5
y =-4x/5 + 3/5 = the perpendicular line through the given point
