Math factorise

(1. 3x(x-y)2-xy(x-y)
=6x(x-y)-xy(x-y)
=(x-y)(6x-xy)

2)4(x-y)-2(x-y)^2
=2(x-y)[2-(x-y)]
=2(x-y)(2-x+y)

3)2(x-3y)^2+4x(x-3y)
=2(x-3y)[(x-3y)+2X]
=2(x-3y)(x-3y+2x)
=2(x-3y)(3x+3y)
=2．3(x-3y)(x+y)
=6(x-3y)(x+y)

hope I can help you~=]