在线等,求100道初一上学期数学先化简再求值的题,要有答案,可以不要过程,大家帮帮忙,老师太jian了

例子:5a-2b+3b-4a-1=a+b-1当a=-1b=2原式=-1+2-1=0题要越简单越好,求大家帮帮忙啦~\(≧▽≦)/~会加悬赏哦... 例子:
5a-2b+3b-4a-1
=a+b-1
当a= -1 b=2
原式=-1+2-1
=0
题要越简单越好,求大家帮帮忙啦~\(≧▽≦)/~ 会加悬赏哦
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(1)9x+6x²-3(x-2/3x-2²),其中X=-2
=9x+6x²-3x+2x+12
=6x²+8x+12 其中X=-2
=6*(-2)²+8*(-2)+12
=24-16+12
=20

(2)1/4(-4x²-2x-8)-(1/2x-1),其中X=1/2
=-x²-1/2x-2-1/2x+1
=-x²-x-1 其中X=1/2
=-(1/2)²-1/2-1
=-1/4-1/2-1
=-7/4

(3)(5a²-3b²)+(a²+b²)-(5a²+3b²),其中a=-1,b=1
=5a²-3b²+a²+b²-5a²-3b²
=a²-5b² 其中a=-1,b=1
=(-1)²-5*1²
=1-5
=-4

(4)2(a²b+ab²)-2(a²b-1)-2ab²-2,其中a=-2,b=2
=2a²b+2ab²-2a²b+2-2ab²-2
=0
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______.

25.一个多项式减去3m4-m3-2m+5得-2m4-3m3-2m2-1,那么这个多项式等于______.

26.-(2x2-y2)-[2y2-(x2+2xy)]=______.

27.若-3a3b2与5ax-1by+2是同类项,则x=______,y=______.

28.(-y+6+3y4-y3)-(2y2-3y3+y4-7)=______.

29.化简代数式4x2-[7x2-5x-3(1-2x+x2)]的结果是______.

30.2a-b2+c-d3=2a+( )-d3=2a-d3-( )=c-( ).

31.3a-(2a-3b)+3(a-2b)-b=______.

32.化简代数式x-[y-2x-(x+y)]等于______.

33.[5a2+( )a-7]+[( )a2-4a+( )]=a2+2a+1.

34.3x-[y-(2x+y)]=______.

35.化简|1-x+y|-|x-y|(其中x<0,y>0)等于______.

36.已知x≤y,x+y-|x-y|=______.

37.已知x<0,y<0,化简|x+y|-|5-x-y|=______.

38.4a2n-an-(3an-2a2n)=______.

39.若一个多项式加上-3x2y+2x2-3xy-4得

2x2y+3xy2-x2+2xy,

则这个多项式为______.

40.-5xm-xm-(-7xm)+(-3xm)=______.

41.当a=-1,b=-2时,

[a-(b-c)]-[-b-(-c-a)]=______.

43.当a=-1,b=1,c=-1时,

-[b-2(-5a)]-(-3b+5c)=______.

44.-2(3x+z)-(-6x)+(-5y+3z)=______.

45.-5an-an+1-(-7an+1)+(-3an)=______.

46.3a-(2a-4b-6c)+3(-2c+2b)=______.

48.9a2+[7a2-2a-(-a2+3a)]=______.

50.当2y-x=5时,5(x-2y)2-3(-x+2y)-100=______.
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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______.

25.一个多项式减去3m4-m3-2m+5得-2m4-3m3-2m2-1,那么这个多项式等于______.

26.-(2x2-y2)-[2y2-(x2+2xy)]=______.

27.若-3a3b2与5ax-1by+2是同类项,则x=______,y=______.

28.(-y+6+3y4-y3)-(2y2-3y3+y4-7)=______.

29.化简代数式4x2-[7x2-5x-3(1-2x+x2)]的结果是______.

30.2a-b2+c-d3=2a+( )-d3=2a-d3-( )=c-( ).

31.3a-(2a-3b)+3(a-2b)-b=______.

32.化简代数式x-[y-2x-(x+y)]等于______.

33.[5a2+( )a-7]+[( )a2-4a+( )]=a2+2a+1.

34.3x-[y-(2x+y)]=______.

35.化简|1-x+y|-|x-y|(其中x<0,y>0)等于______.

36.已知x≤y,x+y-|x-y|=______.

37.已知x<0,y<0,化简|x+y|-|5-x-y|=______.

38.4a2n-an-(3an-2a2n)=______.

39.若一个多项式加上-3x2y+2x2-3xy-4得

2x2y+3xy2-x2+2xy,

则这个多项式为______.

40.-5xm-xm-(-7xm)+(-3xm)=______.

41.当a=-1,b=-2时,

[a-(b-c)]-[-b-(-c-a)]=______.

43.当a=-1,b=1,c=-1时,

-[b-2(-5a)]-(-3b+5c)=______.

44.-2(3x+z)-(-6x)+(-5y+3z)=______.

45.-5an-an+1-(-7an+1)+(-3an)=______.

46.3a-(2a-4b-6c)+3(-2c+2b)=______.

48.9a2+[7a2-2a-(-a2+3a)]=______.

50.当2y-x=5时,5(x-2y)2-3(-x+2y)-100=_____
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