1、=3b-1+5a^2-b-2a^2+4b=3a^2+6b-1=12+3-1=14
2、=-x^2-3x+2-x^2-4+4x=-2x^2+x-2=-50+5-2=-47
3、=3x^2y-2xy^2+2xy-3x^2y-xy+3xy^2=xy^2+xy=-12+6=-6
1、=3b-1+5a^2-b-2a^2+4b=3a^2+6b-1=12+3-1=14
2、=-x^2-3x+2-x^2-4+4x=-2x^2+x-2=-50+5-2=-47
3、=3x^2y-2xy^2+2xy-3x^2y-xy+3xy^2=xy^2+xy=-12+6=-6