1.(-x+2x²+5)+(4x²-3-6x) 2.(3a²-ab+7)-(-4a²+2ab+7) 3.(2a-3b)- [4a+（3a-b]
问题描述：
1.(-x+2x²+5)+(4x²-3-6x) 2.(3a²-ab+7)-(-4a²+2ab+7) 3.(2a-3b)- [4a+（3a-b]
怎么计算
答
1.(-x+2x²+5)+(4x²-3-6x) =-x+2x²+5+4x²-3-6x=6x²-7x+22.(3a²-ab+7)-(-4a²+2ab+7) =3a²-ab+7+4a²-2ab-7=7a²-3ab3.(2a-3b)- [4a+（3a-b] =2a-3b-4a-（3a-b)=-2a-3...