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.
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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
=3-3y4.-2(3x+z)-(-6x)+(-5y+3z)
=-6x-2z+6x-5y+3z
=z-5y5.已知x≤y,x+y-|x-y|
=x+y-(y-x)
=x+y-y+x
=2x6.3x-[y-(2x+y)]
=3x-(y-2x-y)
=3x+2x
=5x7.化简|1-x+y|-|x-y|(其中x＜0,y＞0)
=(1-x+y)-(y-x)
=1-x+y-y+x
=18.化简x-[y-2x-(x+y)]
=x-(y-2x-x-y)
=x+3x=4x9.3a-(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
=611.-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
=014.当2y-x=-5时,5(x-2y)-3(-x+2y)-100
=-5(2y-x)-3(2y-x)-100
=(-5)*(-5)-3*(-5)-100
=-6015.1-[b-2(1-5a)]-(-3b+5a)
=1-(b-2+10a)+3b-5a
=1-b+2-10a+3b-5a=2b-15a+316.-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)²24.3ab²-4a²b+8a²b-7ab²+3ab25.已知A=2x³-2x²+x-4,B=2x³-5x+3,计算A-B