A.计算:1.(a+b)(a-2b)-2(a+2b)(a-b)===2.5x(X^2+2X+1)-(2x+3)(x-5)===

问题描述:

A.计算:
1.(a+b)(a-2b)-2(a+2b)(a-b)
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2.5x(X^2+2X+1)-(2x+3)(x-5)
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