初一口算 100 题 1.3ab-4ab+8ab-7ab+ab=______. 2.7x-(5x-5y)-y=______. 3.23a3bc2-15ab2c+8abc-24a3bc2-8abc=______. 4.-7x2+6x+13x2-4x-5x2=______. 5.2y+(-2y+5)-(3y+2)=______. 6.(2x2-3xy+4y2)+(x2+2xy-3y2)=______. 7.2a-(3a-2b+2)+(3a-4b-1)=______. 13.-6x2-7x2+15x2-2x2=______. 14.2x-(x+3y)-(-x-y)-(x-y)=______. 16.2x+2y-[3x-2(x-y)]=______. 17.5-(1-x)-1-(x-1)=______. 18.( )+(4xy+7x2-y2)=10x2-xy. 19.(4xy2-2x2y)-()=x3-2x2y+4xy2+y3. 21.已知 A=x3-2x2+x-4,B=2x3-5x+3,计算 A+B=______. 22.已知 A=x3-2x2+x-4,B=2x3-5x+3,计算 A-B=______. 23.若 a=-0
5,代数式-(|a2b|-|ab2|)的值为______. 25.一个多项式减去 3m4-m3-2m+5 得-2m4-3m3-2m2-1,那么这个多项式等于______. 26.-(2x2-y2)-[2y2-(x2+2xy)]=______. 27.若-3a3b2 与 5ax-1by+2 是同类项,则 x=______,y=______. 28.(-y+6+3y4-y3)-(2y2-3y3+y4-7)=______. 29.化简代数式4x2-[7x2-5x-3(1-2x+x2)]的结果是______. 30.2a-b2+c-d3=2a+()-d3=