计算(3xy²)·(-2xy),(2x-y)²-4(x+y)(x-2y),
问题描述:
计算(3xy²)·(-2xy),(2x-y)²-4(x+y)(x-2y),
答
(3xy²)·(-2xy)
=-6x²y³
(2x-y)²-4(x+y)(x-2y)
=4x²-4xy+y²-4(x²-2xy+xy-2y²)
=4x²-4xy+y²-4x²+4xy+8y²
=9y²
答
原式=-6x²y³
原式=4x²-4xy+y²-4(x²-xy-2y²)
=4x²-4xy+y²-4x²+4xy+8y²
=9y²