81(x+y)²-121(m+n)² (x²+y²)²-x²y_数学解答

81(x+y)²-121(m+n)² (x²+y²)²-x²y² (2m-n)²-(3m+2n)² 因式
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人气：256 ℃　时间：2019-10-08 20:05:20

解答

81(x+y)²-121(m+n)² =（9x+9y-11m-11n)(9x+9y+11m+11n)(x²+y²)²-x²y² =(x²+xy+y²)(x²-xy+y²)(2m-n)²-(3m+2n)²=(2m-n+3m+2n)(2m-n-3m-2n)=-(5m+n)...