Perpendicular to 3x + 4y + 9 = 0
4y = -3x - 9
y = (-3/4)x - 9/4
slope = -3/4
Perpendicular slope = 4/3
Point (-3,3)
Point-slope form
y - y1 = m(x - x1)
y - 3 = (4/3)(x - -3)
y - 3 = (4/3)(x + 3)
y - 3 = (4/3)x + 4
y - 7 = (4/3)x
(-4/3)x + y - 7 = 0
a = -4/3, b = 1