数学用乘法公式计算(x+y+1)(x+y-1)(2x-y-3)²
问题描述:
数学用乘法公式计算
(x+y+1)(x+y-1)
(2x-y-3)²
答
(x+y+1)(x+y-1)
=(x+y)²-1
=x²+2xy+y²-1
(2x-y-3)²
=(2x-y)²-2(2x-y)+3
=4x²+4xy+y²-4x+2y+9