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1.5a(m-n)-10a(m-n)2.(x+y)²(x-y)+(x+y)(x-y)²3.x²y²-0.044.-m²+1/165.9a²-12a+46.4x²+20xy+25y²7.x²+7x+128.x²-4xy-96y²

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答案和解析
1.5a(m-n)-10a(m-n)
=-5a(m-n)
2.(x+y)²(x-y)+(x+y)(x-y)²
=(x+y)(x-y)(x+y+x-y)
=2x(x+y)(x-y)
3.x²y²-0.04
=(xy+0.2)(xy-0.2) (平方差)
4.-m²+1/16
=-(m+1/4)(m-1/4) (平方差)
5.9a²-12a+4
=(3a-2)^2 (完全平方)
6.4x²+20xy+25y²
=(2x+5y)^2 (完全平方)
7.x²+7x+12
=(x+3)(x+4) (交叉相乘)
8.x²-4xy-96y²
=(x+8y)(x-12y) (交叉相乘)