求7下化简求值题,30道,

1个回答

  • 1.(4x2-8x+5)-(x3+3x2-6x+2).

    2.(0.3x3-x2y+xy2-y3)-(-0.5x3-x2y+0.3xy2).

    3.-{2a2b-[3abc-(4ab2-a2b)]}.

    4.(5a2b+3a2b2-ab2)-(-2ab2+3a2b2+a2b).

    5.(x2-2y2-z2)-(-y2+3x2-z2)+(5x2-y2+2z2).

    6.(3a6-a4+2a5-4a3-1)-(2-a+a3-a5-a4).

    7.(4a-2b-c)-5a-[8b-2c-(a+b)].

    8.(2m-3n)-(3m-2n)+(5n+m).

    9.(3a2-4ab-5b2)-(2b2-5a2+2ab)-(-6ab).

    10.xy-(2xy-3z)+(3xy-4z).

    11.(-3x3+2x2-5x+1)-(5-6x-x2+x3).

    12.3x-(2x-4y-6x)+3(-2z+2y).

    13.(-x2+4+3x4-x3)-(x2+2x-x4-5).

    14.若A=5a2-2ab+3b2,B=-2b2+3ab-a2,计算A+B.

    15.已知A=3a2-5a-12,B=2a2+3a-4,求2(A-B).

    16.2m-{-3n+[-4m-(3m-n)]}.

    17.5m2n+(-2m2n)+2mn2-(+m2n).

    18.4(x-y+z)-2(x+y-z)-3(-x-y-z).

    19.2(x2-2xy+y2-3)+(-x2+y2)-(x2+2xy+y2).

    20.2(a2-ab-b2)-3(4a-2b)+2(7a2-4ab+b2).

    21.4x-2(x-3)-3[x-3(4-2x)+8].

    22.已知a+b=2,a-b=-1,求3(a+b)2(a-b)2-5(a+b)2×(a-b)2的值.

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

    24.求(3x2y-2xy2)-(xy2-2x2y),其中x=-1,y=2.

    25.已知|x+1|+(y-2)2=0,求代数式5(2x-y)-3(x-4y)的值.

    26.当P=a2+2ab+b2,Q=a2-2ab-b2时,求P-[Q-2P-(P-Q)].

    27.求2x2-{-3x+5+[4x2-(3x2-x-1)]}的值,其中x=-3.

    28.当x=-2,y=-1,z=3时,求5xyz-{2x2y-[3xyz-(4xy2-x2y)]}的值.

    29.已知A=x3-5x2,B=x2-6x+3,求A-3(-2B).

    30.A=11x3+8x2-6x+2,B=7x3-x2+x+3,求2(3A-2B).