已知x+y=-2,xy=3,求2(xy-3x)-3(2y-xy)的值
问题描述:
已知x+y=-2,xy=3,求2(xy-3x)-3(2y-xy)的值
答
原式=2xy-6x-6y+3xy
=5xy-6(x+y)
=5×3-6×(-2)
=27