NOTE: Perpendicular line have opposite(negative) reciprocal slope
For the line y = 1/4x - 3 it has slope of 1/4
but the perpendicular line with point (-4,6) has slope of -4 (negative reciprocal)
(y - y1) = m (x - x1)
(y - 6 ) = -4 (x --4)
(y - 6) = -4 (x + 4)
y - 6 = -4x -16
y = -4x -16 + 6
y = -4x -10