【4】(-2x+3y)(-2x-3y) 【5】(- - 知识问答

【4】(-2x+3y)(-2x-3y) 【5】(-1/4x-2y)(-1/4x+2y) 【6】x^2+(y-x)(y+x

2个回答

【4】(-2x+3y)(-2x-3y)
=-(2x-3y)[-(2x+3y) ]
=(2x-3y)(2x+3y)
=4x²-9y²
【5】(-1/4x-2y)(-1/4x+2y)
=-(1/4x+2y)[-(1/4x-2y) ]
=(1/4x+2y)(1/4x-2y)
=1/8x²-4y²
【6】x²+(y-x)(y+x)
=x²+y²-x²
=y²
【7】(a^n+b)(a^n-b)
=a^2n-b²
【8】(a+1)(a-1)(a²+1)
=(a²-1)(a²+1)
=a^4-1

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