整式的化简求值
整式化简求值的步骤有去括号、合并同类项、代入求值。
利用整式解决实际问题的步骤有设未知数、列整式、代入求值。
以下是30道整式的化简求值：
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)=______．
8．-6x2-7x2+15x2-2x2＝______．
9．2x-(x+3y)-(-x-y)-(x-y)＝______．
10．2x+2y-[3x-2(x-y)]=______．
11．5-(1-x)-1-(x-1)=______．
12．( )+(4xy+7x2-y2)=10x2-xy．
13．(4xy2-2x2y)-( )=x3-2x2y+4xy2+y3．
14．已知A=x3-2x2+x-4，B=2x3-5x+3，计算A+B=______．
15．已知A=x3-2x2+x-4，B=2x3-5x+3，计算A-B=______．
16．若a=-0.2，b=0.5，代数式-(|a2b|-|ab2|)的值为______．
17．一个多项式减去3m4-m3-2m+5得-2m4-3m3-2m2-1，那么这个多项式等于______．
18．-(2x2-y2)-[2y2-(x2+2xy)]=______．
19．若-3a3b2与5ax-1by+2是同类项，则x=______，y=______．
20．(-y+6+3y4-y3)-(2y2-3y3+y4-7)＝______．
21．化简代数式4x2-[7x2-5x-3(1-2x+x2)]的结果是______．
22．2a-b2+c-d3=2a+( )-d3=2a-d3-( )=c-( )．
23．3a-(2a-3b)+3(a-2b)-b=______．
24．化简代数式x-[y-2x-(x+y)]等于______．
25．[5a2+( )a-7]+[( )a2-4a+( )]=a2+2a+1．
26．3x-[y-(2x+y)]=______．
27．化简|1-x+y|-|x-y|(其中x＜0，y＞0)等于______．
28．已知x≤y，x+y-|x-y|=______．
29．已知x＜0，y＜0，化简|x+y|-|5-x-y|=______．
30．4a2n-an-(3an-2a2n)＝______．
