Question

30道整式的加减混合运算题.要有步骤和答案，写详细。。。

初一水平的就成。。。哎╮(╯▽╰)╭ 要有次数，括号神马的，，，步骤写详细，3Q。。。

Answer 1

前面15个有答案，后面15没有
1.（x²-7x-2)-(-2x²+4x-1)

= x²-7x-2+2x²-4x+1

=3x²-11x-1
2. -2y³+(3xy²-x²y)-2(xy²-y³)
=-2y³+3xy²-x²y-2xy²+2y³
=xy²-x²y
3. 2y+(-2y+5)-(3y+2)
=2y-2y+5-3y-2
=3-3y
4. -2(3x+z)-(-6x)+(-5y+3z)
=-6x-2z+6x-5y+3z
=z-5y
5. 已知x≤y，x+y-|x-y|
=x+y-(y-x)
=x+y-y+x
=2x
6. 3x-[y-(2x+y)]
=3x-(y-2x-y)
=3x+2x
=5x
7. 化简|1-x+y|-|x-y|(其中x＜0，y＞0)
=(1-x+y)-(y-x)
=1-x+y-y+x
=1
8. 化简x-[y-2x-(x+y)]
=x-(y-2x-x-y)
=x+3x
=4x
9. 3a-(2a-3b)+3(a-2b)-b
=3a-2a+3b+3a-6b-b
=4a-4b
10.5-(1-x)-1-(x-1)
=5+1+x-1-x+1
=6
11.-9(x-2)²+(x+5)²
=-9（x²-4x+4）+(x²+10x+25)
=-9x²+36x-36+x²+10x+25
=-8x²+46x-11
12.(2x²-y²)-[2y²-(x²+2xy)]
=2x²-y²-(2y²-x²-2xy)
=2x²-y²-2y²+x²+2xy
=3x²-3y²+2xy
13.2(a²b+ab²)-2(a²b-1)-2ab²-2
=2a²b+2ab²-2a²b+2-2ab²-2
=0
14.当2y-x=-5时，5(x-2y)-3(-x+2y)-100
=-5(2y-x)-3(2y-x)-100
=(-5)*(-5)-3*(-5)-100
=-60
15.1-[b-2(1-5a)]-(-3b+5a)
=1-(b-2+10a)+3b-5a
=1-b+2-10a+3b-5a
=2b-15a+3
16.-2(3x+z)-(-6x)+(-5y+3z)

17.-5an-an+1-(-7an+1)+(-3an)

18.2a-（3a-2b+2）+（3a-4b-1)

19.3a-(2a-4b-6c)+3(-2c+2b)

20.9a²+[7a²-2a-(-a²+3a)]

21.2a-(3a-2b+2)+(3a-4b-1)

22.2a²-(3a²-2b²+2ab+2)+(3a²-4b²-1)

23.2y²+(2y-5)²-(3y+2)²

24.3ab²-4a²b+8a²b-7ab²+3ab

25.已知A=2x³-2x²+x-4，B=2x³-5x+3，计算A-B

26.4x²-[7x²-5x-3(1-2x+x²)]

27.2x+2y-[3x-2(x-y)]

28.(4xy²-2x²y)-( )=x3-2x²y+4xy²+y³

29.若一个多项式加上-3x²y+2x²-3xy-4得2x²y+3xy²-x²+2xy则这个多项式为______．

30.已知A=a²+2b²-3c²，B=-b²-2c²+3a²，C=c²+2a²-3b²，求(A-B)+C

31.2x-(x+3y)-(-x-y)-(x-y)