先化简，再求值:2(x^2 y+xy)-3(x^2 y-xy)-4x^2 y，其中x=-1，y=1

Question

如题所述

Answer 1

2(x^2 y+xy)-3(x^2 y-xy)-4x^2 y，
=2x²y+2xy-3x²y+3xy-4x²y
=-5x²y+5xy
=-5x（-1）²x1+5x（-1）x1²
=-5-5
=-10