Factor the following:
-4 y^2 + 3 x y - 12 y + 9 x
Factor terms by grouping. -4 y^2 + 3 x y - 12 y + 9 x = (3 x y - 4 y^2) + (9 x - 12 y) = y (3 x - 4 y) + 3 (3 x - 4 y):
y (3 x - 4 y) + 3 (3 x - 4 y)
Factor 3 x - 4 y from y (3 x - 4 y) + 3 (3 x - 4 y):
=(3x - 4y) (y + 3)
