As the midpoint is a point on the perpendicular line, we can solve by eliminating the other equations, like this: Check if the point (-1,-2) is on the line y=-4x-4: -4(-1)-4=0 is differente from -2. -4(-1)-6=-2, so (-1,-2) is on the line y=-4x-6. We check also for the other equation like this: Third equation: (-1)-4 = -5 not equal to -2. Fourth equation: (-1)-6=-7 not equal to -2. So the correct answer is the line y=-4x-6
form, 
is the y-intercept.
