初一上册数学经典练习题 化简求值 急、、

3个回答

  • 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=______.