2x²y-2y²x+2xy²+2yx²=2x²y+2x²y-2y²x+2y²x=4x²y太谢谢了 可以告诉我这道题吗麻烦您了，万分感谢2a²-3ab-1+b+3ab-1/2a²+12a²-3ab-1+b+3ab-1/2a²+1=2a²+(-3ab+3ab)-1/2a²+1-1+b=2a²-1/2a²+b