初一数学下（多项式难题）2题先化简，在求值 10道初一数学化简求值题

\u521d\u4e00\u6570\u5b66\u9898\uff0c\u5148\u5316\u7b80\u518d\u6c42\u503c\u7684\u9898\u5e26\u7b54\u6848

3\uff0e3ab-4ab+8ab-7ab+ab=______\uff0e
4\uff0e7x-(5x-5y)-y=______\uff0e
5\uff0e23a3bc2-15ab2c+8abc-24a3bc2-8abc=______\uff0e
6\uff0e-7x2+6x+13x2-4x-5x2=______\uff0e
7\uff0e2y+(-2y+5)-(3y+2)\uff1d______\uff0e
11\uff0e(2x2-3xy+4y2)+(x2+2xy-3y2)=______\uff0e
12\uff0e2a-(3a-2b+2)+(3a-4b-1)=______\uff0e
13\uff0e-6x2-7x2+15x2-2x2\uff1d______\uff0e
14\uff0e2x-(x+3y)-(-x-y)-(x-y)\uff1d______\uff0e
16\uff0e2x+2y-[3x-2(x-y)]=______\uff0e
17\uff0e5-(1-x)-1-(x-1)=______\uff0e
18\uff0e(
)+(4xy+7x2-y2)=10x2-xy\uff0e
19\uff0e(4xy2-2x2y)-(
)=x3-2x2y+4xy2+y3\uff0e
21\uff0e\u5df2\u77e5A=x3-2x2+x-4\uff0cB=2x3-5x+3\uff0c\u8ba1\u7b97A+B=______\uff0e
22\uff0e\u5df2\u77e5A=x3-2x2+x-4\uff0cB=2x3-5x+3\uff0c\u8ba1\u7b97A-B=______\uff0e
23\uff0e\u82e5a=-0.2\uff0cb=0.5\uff0c\u4ee3\u6570\u5f0f-(|a2b|-|ab2|)\u7684\u503c\u4e3a______\uff0e
25\uff0e\u4e00\u4e2a\u591a\u9879\u5f0f\u51cf\u53bb3m4-m3-2m+5\u5f97-2m4-3m3-2m2-1\uff0c\u90a3\u4e48\u8fd9\u4e2a\u591a\u9879\u5f0f\u7b49\u4e8e______\uff0e
26\uff0e-(2x2-y2)-[2y2-(x2+2xy)]=______\uff0e
27\uff0e\u82e5-3a3b2\u4e0e5ax-1by+2\u662f\u540c\u7c7b\u9879\uff0c\u5219x=______\uff0cy=______\uff0e
28\uff0e(-y+6+3y4-y3)-(2y2-3y3+y4-7)\uff1d______\uff0e
29\uff0e\u5316\u7b80\u4ee3\u6570\u5f0f4x2-[7x2-5x-3(1-2x+x2)]\u7684\u7ed3\u679c\u662f______\uff0e
30\uff0e2a-b2+c-d3=2a+(
)-d3=2a-d3-(
)=c-(
)\uff0e
31\uff0e3a-(2a-3b)+3(a-2b)-b=______\uff0e
32\uff0e\u5316\u7b80\u4ee3\u6570\u5f0fx-[y-2x-(x+y)]\u7b49\u4e8e______\uff0e
33\uff0e[5a2+(
)a-7]+[(
)a2-4a+(
)]=a2+2a+1\uff0e
34\uff0e3x-[y-(2x+y)]=______\uff0e
35\uff0e\u5316\u7b80|1-x+y|-|x-y|(\u5176\u4e2dx\uff1c0\uff0cy\uff1e0)\u7b49\u4e8e______\uff0e
36\uff0e\u5df2\u77e5x\u2264y\uff0cx+y-|x-y|=______\uff0e
37\uff0e\u5df2\u77e5x\uff1c0\uff0cy\uff1c0\uff0c\u5316\u7b80|x+y|-|5-x-y|=______\uff0e
38\uff0e4a2n-an-(3an-2a2n)\uff1d______\uff0e
39\uff0e\u82e5\u4e00\u4e2a\u591a\u9879\u5f0f\u52a0\u4e0a-3x2y+2x2-3xy-4\u5f97
2x2y+3xy2-x2+2xy\uff0c
\u5219\u8fd9\u4e2a\u591a\u9879\u5f0f\u4e3a______\uff0e
40\uff0e-5xm-xm-(-7xm)+(-3xm)=______\uff0e
41\uff0e\u5f53a=-1\uff0cb=-2\u65f6\uff0c
[a-(b-c)]-[-b-(-c-a)]\uff1d______\uff0e
43\uff0e\u5f53a=-1\uff0cb=1\uff0cc=-1\u65f6\uff0c
-[b-2(-5a)]-(-3b+5c)\uff1d______\uff0e
44\uff0e-2(3x+z)-(-6x)+(-5y+3z)=______\uff0e
45\uff0e-5an-an+1-(-7an+1)+(-3an)\uff1d______\uff0e
46\uff0e3a-(2a-4b-6c)+3(-2c+2b)=______\uff0e
48\uff0e9a2+[7a2-2a-(-a2+3a)]=______\uff0e
50\uff0e\u5f532y-x=5\u65f6\uff0c5(x-2y)2-3(-x+2y)-100=_____

1\uff0e\u82e5a=-0.2,b=0.5,\u4ee3\u6570\u5f0f-(|a2b|-|ab2|)\u7684\u503c\u4e3a______\uff0e
2\uff0e\u4e00\u4e2a\u591a\u9879\u5f0f\u51cf\u53bb3m4-m3-2m+5\u5f97-2m4-3m3-2m2-1,\u90a3\u4e48\u8fd9\u4e2a\u591a\u9879\u5f0f\u7b49\u4e8e______\uff0e
3\uff0e-(2x2-y2)-[2y2-(x2+2xy)]=______\uff0e
4\uff0e\u82e5-3a3b2\u4e0e5ax-1by+2\u662f\u540c\u7c7b\u9879,\u5219x=______,y=______\uff0e
5\uff0e(-y+6+3y4-y3)-(2y2-3y3+y4-7)\uff1d______\uff0e
6\uff0e\u5316\u7b80\u4ee3\u6570\u5f0f4x2-[7x2-5x-3(1-2x+x2)]\u7684\u7ed3\u679c\u662f______\uff0e
7\uff0e2a-b2+c-d3=2a+( )-d3=2a-d3-( )=c-( )\uff0e
8\uff0e3a-(2a-3b)+3(a-2b)-b=______\uff0e
9\uff0e\u5316\u7b80\u4ee3\u6570\u5f0fx-[y-2x-(x+y)]\u7b49\u4e8e______\uff0e
10\uff0e[5a2+( )a-7]+[( )a2-4a+( )]=a2+2a+1\uff0e

多项式化简求值的方法是：先化简，再求值。多项式化简涉及较多的是整式的加减：其实质是去括号和合并同类项，其一般步骤为：（1）如果有括号，那么先去括号；（2）如果有同类项，再合并同类项。注：整式加减的最后结果中不能含有同类项，即要合并到不能再合并为止。整式的加减即合并同类项。把同类项相加减，不能计算的就直接拉下来。合并同类项时要注意以下三点： ①要掌握同类项的概念，会辨别同类项，并准确地掌握判断同类项的两条标准.字母和字母指数； ②明确合并同类项的含义是把多项式中的同类项合并成一项，经过合并同类项，式的项数会减少，达到化简多项式的目的； ③“合并”是指同类项的系数的相加，并把得到的结果作为新的系数，要保持同类项的字母和字母的指数不变。

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