1、-3x^2y+(-2xy^2)+3x^2y-3xy^2
=-3x²y-2xy²+3x²y-3xy²
=-5xy²
2、2x^2-3x+5x^2-3+x^2+7-6x
=8x²-9x+4
3、1/2x-(2x-2/3y^2)+(-3/2x+2y^2)
=x/2-2x+2y²/3-3x/2+2y²
=-3x+8y²/3
4、(x^2+4x+3)-2(5x^2-2x+7)
=x²+4x+3-10x²+4x-14
=-9x²+8x-11第2题要合并当然合并了的，不能再合并了第3题看不懂= =3、1/2x-(2x-2/3y^2)+(-3/2x+2y^2) =x/2-2x+2y²/3-3x/2+2y²=(1/2-2-3/2)x+(2/3+2)y²=-3x+(8/3)y²2y²/3-3x/2+2y ²这里是什么 = =你叫我怎么写啊百度知道只能这样，也可写成(2/3)y²-(3/2)x+2y²