-2n-(3n-1) a-(5a-3b)+(2b-a) -3(2s-5)+6s 1-(2a-1)-(3a+3) 3(-ab+2a)-(3a-b) 14(abc-2a)+3(6a-2abc) 3(xy-2z)+(-xy+3z) -4(pq+pr)+(4pq+pr)
1.-2n-(3n-1)
原式=-2n-3n+1
=-5n+1
2.a-(5a-3b)+(2b-a)
原式=a-5a+3b+2b-a
=-5a+5b
3.-3(2s-5)+6s
原式=-6s+15+6s
=15
4.1-(2a-1)-(3a+3)
原式=1-2a+1-3a-3
=-1-5a
5.3(-ab+2a)-(3a-b)
原式=（-3ab+6a）-3a+b
=-3ab+6a-3a+b
=-3ab+3a+b
6.14(abc-2a)+3(6a-2abc)
原式=14 abc-28a+（18a-6abc）
=14abc-28a+18a-6abc
=8abc-10a
7.3(xy-2z)+(-xy+3z)
解 原式=3xy-6z-xy+3z
=2xy-3z
8.-4(pq+pr)+(4pq+pr)
原式=-（4pq+4pr）+4pq+pr
=-4pq-4pr+4pq+4pr
3ab-4ab+8ab-7ab+ab=______． 7x-(5x-5y)-y=______． 23a3bc2-15ab2c+8abc-24a3bc2-8abc=______． -7x2+6x+13x2-4x-5x2=______． 2y+(-2y+5)-(3y+2)＝______． (2x2-3xy+4y2)+(x2+2xy-3y2)=______． 2a-(3a-2b+2)+(3a-4b-1)=______． -6x2-7x2+15x2-2x2＝______． 2x-(x+3y)-(-x-y)-(x-y)＝______． 2x+2y-[3x-2(x-y)]=______． 5-(1-x)-1-(x-1)=______． (4xy2-2x2y)-( )=x3-2x2y+4xy2+y3． 已知A=x3-2x2+x-4,B=2x3-5x+3,计算A+B=______． 已知A=x3-2x2+x-4,B=2x3-5x+3,计算A-B=______． 若a=-0.2,b=0.5,代数式-(|a2b|-|ab2|)的值为______．
3．3ab-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-( )．