(1)(-2xy3z2)4 =(-2)4•x4•(y3)4•(z2)4 =16x4y12z8; (2)(xy+4)(xy-4) =(xy)2-42 =x2y2-16; (3)(2x-3)(x-1) =2x2-2x-3x+3 =2x2-5x+3; (4)(54x2y-108xy2-36xy)÷(18xy) =54x2y÷18xy-108xy2÷18xy-36xy÷18xy =3x-6y-2; (5)a2bc3•(-2a2b2c)2 =a2bc3•4a4b4c2 =2a6b5c5; (6)(x+y)2-(x-y)2 =[(x+y)+(x-y)][(x+y)-(x-y)] =(x+y+x-y)(x+y-x+y) =2x•2y =4xy. |