化简求值: [2x^2-(x+y)(x-y)][(-x-y)(y-x)+2y^2],其中x=1,y=2. 求详细过程~

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化简求值:[2x^2-(x+y)(x-y)][(-x-y)(y-x)+2y^2],其中x=1,y=2.求详细过程~化简求值:[2x^2-(x+y)(x-y)][(-x-y)(y-x)+2y^2],其中

化简求值: [2x^2-(x+y)(x-y)][(-x-y)(y-x)+2y^2],其中x=1,y=2. 求详细过程~
化简求值: [2x^2-(x+y)(x-y)][(-x-y)(y-x)+2y^2],其中x=1,y=2. 求详细过程~

化简求值: [2x^2-(x+y)(x-y)][(-x-y)(y-x)+2y^2],其中x=1,y=2. 求详细过程~
[2x²-(x+y)(x-y)][(-x-y)(y-x)+2y²]
= [2x²-(x²-y²)][-(x+y)(-(x-y))+2y²] (一个负号提出来,再一个负号提出来,负负得正抵消)
=(2x²-x²+y²)(2y²+x²-y²)
=(x²+y²)(x²+y²)
=(x²+y²)²
=(1+4)²=25

[2x^2--(x+y)(x-y)][(--x--y)(y--x)+2y^2]
=[2x^2--(x^2--y^2)][(x^2--y^2)+2y^2]
=(x^2+y^2)(x^2+y^2)
=(x^2+y^2)^2
当 x=1, y=2 时,
原式的值=(1^2+2^2)^2
=(1+4)^2
=5^2
=25。