Factorise: 5x2- y2- 4xy + 3x - 3y
5x2- y2- 4xy + 3x - 3y = x2 + 4x2 - y2 - 4xy + 3x - 3y = (x2 - y2) + (4x2 - 4xy) + (3x - 3y) = (x - y)(x + y) + 4x (x - y) + 3(x - y) = (x - y)[(x + y) + 4x + 3] = (x - y)(x + y + 4x + 3) = (x - y)(5x + y + 3).