求21道化简求值的题,急!例题:-2(a+1)-1/2(4a-2a)其中a等于-2要求:初一上册的

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求21道化简求值的题,急!例题:-2(a+1)-1/2(4a-2a)其中a等于-2要求:初一上册的
求21道化简求值的题,急!
例题:-2(a+1)-1/2(4a-2a)其中a等于-2
要求:初一上册的

求21道化简求值的题,急!例题:-2(a+1)-1/2(4a-2a)其中a等于-2要求:初一上册的
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______.