b) 4xy^2 – 4x62y – y^3
b) 4xy2 – 4x2y – y3
b) 4xy2 – 4x2y – y3
= –y(–4xy + 4x2 + y2)
= ‒y(4x2 ‒ 4xy + y2)
= ‒y[(2x)2 ‒ 2.2x.y + y2]
= ‒y(2x – y)2.