2x^2-2y^2)-3(xy^3+x^2)+3(xy^3+y^2)其中x=-1,y=2化简求值

更新时间2022-07-20 16:42:22

2x²-2y²-3(xy³+x²)+3(xy³+y²)

=2x²-2y²-3xy³-3x²+3xy³+3y²

=(2x²-3x²)+(-2y²+3y²)+(-3xy³+3xy³)

=-x²+y²

=-(-1)²+2²

=-1+4

=3