Question

[(x的二次方+的y二次方)-(x-y)的二次方+2y(x-y)]除以4,

其中x=负三分之一，y=3

Answer 1

原式=(x²+y²-x²+2xy-y²+2xy-2y²)/4
=(4xy-2y²)/4
=xy-y²/2 把x=-1/3，y=3代入
=-1-9/2
=-11/2

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Answer 2

[(x的二次方+的y二次方)-(x-y)的二次方+2y(x-y)]除以4
=(x²+y²-x²+2xy-y²+2xy-2y²)/4
=(4xy-2y²)/4
=xy-y²/2
当x=-1/3 ，y=3时
原式=-1-9/2
=-11/2

Answer 3

[(x^2+y^2)-(x-y)^2+2y(x-y)]/4
=[x^2+y^2-x^2+2xy-y^2+2xy-2y^2]/4
=(4xy-2y^2)/4
=xy-y^2/2
=-1/3*3-3^2
=-10

Answer 4

您好：

[(x的二次方+的y二次方)-(x-y)的二次方+2y(x-y)]除以4,
=（x²+y²-x²+2xy-y²+2xy-2y²）÷4
=（4xy-2y²）/4
=xy-1/2y²
=(-1/3)x3-1/2x3²
=-1-9/2
=-11/2

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