Question

若x(x-1)-(x²-y)=-6，求(x²+y²)/2-xy的值

若x(x-1)-(x²-y)=-6，求(x²+y²)/2-xy的值
若x(x-1)-(x²-y)=-6，求(x²+y²)/2-xy的值
若x(x-1)-(x²-y)=-6，求(x²+y²)/2-xy的值
若x(x-1)-(x²-y)=-6，求(x²+y²)/2-xy的值
若x(x-1)-(x²-y)=-6，求(x²+y²)/2-xy的值
若x(x-1)-(x²-y)=-6，求(x²+y²)/2-xy的值

Answer 1

x(x-1)-(x²-y)=-6
得：x²-x-x²+y=-6
解得：x-y=6
所以（x-y）²=6²
x²-2xy+y²=36
所以x²+y²=36+2xy

（x²+y²)/2-xy
=(36+2xy)/2-xy
=18+xy-xy
=18

Answer 2

前面化简的x-y=6,后面是（x-y)^2除以2=18

追问

你的不太完整,不过我自己也好了