Factorise \(8xy + 2z(8x-3y) -12 {z}^{2}\) completely. Show out workings, please.
Factor the following:
8 x y+2 z (8 x-3 y)-12 z^2
The factors of -96 x y that sum to 2 (8 x-3 y) are -6 y z and 16 x z.
So, -12 z^2+2 (8 x-3 y) z+8 x y = -12 z^2-6 y z+16 x z+8 x y:
-12 z^2-6 y z+16 x z+8 x y
-12 z^2-6 y z+16 x z+8 x y = 4 z (4 x-3 z)+2 y (4 x-3 z):
4 z (4 x-3 z)+2 y (4 x-3 z)
Factor 4 x-3 z out of 4 z (4 x-3 z)+2 y (4 x-3 z), resulting in (4 x-3 z) (4 z+2 y):
(4 x-3 z) (4 z+2 y)
Factor 2 out of 4 z+2 y:
Answer: | 2 (2 z+y) (4 x-3 z)