已知x(x-1)-(x方-y)+2=0 求(x方+ - 知识问答

已知x(x-1)-(x方-y)+2=0 求(x方+y方)/2-xy

1个回答

∵x（x-1)-(x²-y)+2=0
∴x²-x-x²+y+2=0
∴x-y=2
又∵原式=1/2×(x²+y²-2xy)
=1/2×（x-y)²
=1/2×4
=2

相关问题