推倒公式:(x+y)(x*x-3x+y*y)=x*x*x+y*y*y怎么做.

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推倒公式:(x+y)(x*x-3x+y*y)=x*x*x+y*y*y怎么做.推倒公式:(x+y)(x*x-3x+y*y)=x*x*x+y*y*y怎么做.推倒公式:(x+y)(x*x-3x+y*y)=x

推倒公式:(x+y)(x*x-3x+y*y)=x*x*x+y*y*y怎么做.
推倒公式:(x+y)(x*x-3x+y*y)=x*x*x+y*y*y怎么做.

推倒公式:(x+y)(x*x-3x+y*y)=x*x*x+y*y*y怎么做.
-3x应为-xy
右边=x³+x²y-x²y-xy²+xy²+y³
=x²(x+y)-xy(x+y)+y²(x+y)
=(x+y)(x²-xy+y²)=左边

错了
是(x+y)(x²-xy+y²)
=x³-x²y+xy²+x²y-xy²+y³
=x³+y³

是(x y)(x²-xy y²) =x³-x²y xy² x²y-xy² y³ =x³ y³....求采纳,亲*****