3ab-4ab+8ab-7ab+ab=______.
4.7x-(5x-5y)-y=______.
5.23a3bc2-15ab2c+8abc-24a3bc2-8abc=______.
6.-7x2+6x+13x2-4x-5x2=______.
7.2y+(-2y+5)-(3y+2)=______.
11.(2x2-3xy+4y2)+(x2+2xy-3y2)=______.
12.2a-(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=-0.2,b=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=2a-d3-( )=c-( ).
31.3a-(2a-3b)+3(a-2b)-b=______.
32.化简代数式x-[y-2x-(x+y)]等于______.
33.[5a2+( )a-7]+[( )a2-4a+( )]=a2+2a+1.
34.3x-[y-(2x+y)]=______.
35.化简|1-x+y|-|x-y|(其中x0)等于______.
36.已知x≤y,x+y-|x-y|=______.
37.已知x