(x+2y-5)^2和（x-2y-1)(x+2y-1)的结果

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(x+2y-5)^2和（x-2y-1)(x+2y-1)的结果
(x+2y-5)^2和（x-2y-1)(x+2y-1)的结果

(x+2y-5)^2和（x-2y-1)(x+2y-1)的结果
解
(x+2y-5)²
=(x+2y)²-10(x+2y)+25
=x²+4xy+4y²-10x-20y+25
(x-2y-1)(x+2y-1)
=[(x-1)-2y][(x-1)+2y]
=(x-1)²-(2y)²
=x²-2x+1-4y²