1.6a(b-a)²-2(a-b)³
=6a(a-b)²-2(a-b)³
=2(a-b)²(3a-a+b)
=2(a-b)²(2a+b)
2.x(x+y)(x-y)-x(y+x)²
=x(x+y)(x-y-x-y)
=-2xy(x+y)