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(x-y)^2(x+y)^2两种方法

题目详情
(x-y)^2(x+y)^2两种方法
▼优质解答
答案和解析
(1)(x-y)²(x+y)²
=(x²-2xy+y²)(x²+2xy+y²)
=x^4+2x³y+x²y²-2x³y-4x²y²-2xy³+x²y²+2xy³+y^4
=x^4+-2x²y²+y^4
(2)(x-y)²(x+y)²
=[(x-y)(x+y)]²
=(x²-y²)²
=x^4-2x²y²+y^4.