Question

已知 x(x-1)-(x的平方-y)=-3 求 2xy-x的平方+3-y的平方 要过程 谢谢

Answer 1

x(x-1)-(x²-y)=-3
x²-x-x²+y=-3
x-y=3
2xy-x²+3-y²
=-(x²+y²-2xy)+3
=-(x-y)²+3
=-9+3
=-6

Answer 2

x（x-1）-(x² -y)=-3
x² -x-x² +y=-3
-x+y=-3
x-y=3
2xy-x² +3-y²
=-(x² -2xy+y² )+3
=-(x-y)² +3
=-(3)² +3
=-9+3
=-6