(x+y)²-(x-y)(x+y)-(xy)²÷(xy)=x²+y²+2xy-(x²-y²)-xy=2y²+xy.
方程组｛3x+2y=7 3x+y=5},1式减去2式得y=2,带入得x=1.
所以(x+y)²-(x-y)(x+y)-(xy)²÷(xy)=2y²+xy=8+2=10.
先化简在求值(x+y)²-(x-y)(x+y)-(xy)²÷(xy),其中x,y是方程组『3x+2y
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