[12(x+y)的立方+3(x+y)(x-y)的平方]÷6(x+y)=

问题描述:

[12(x+y)的立方+3(x+y)(x-y)的平方]÷6(x+y)=

[12(x+y)的立方+3(x+y)(x-y)的平方]÷6(x+y)
=2(x+y)²+1/2(x-y)²
=2x²+4xy+y²+0.5x²-xy+0.5y²
=2.5x²+3xy+2.5y²
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