3x 2y括起来的立方
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1的立方+2的立方+3的立方+4的立方+5的立方+.+98的立方+99的立方+100的立方=(1+2+3+...+100)^2=(100*101/2)^2=5050^2=25502500
原式=x3-2y3-3x2y-3x3+3y3+7x2y=-2x3+y3+4x2y
因为:1^3+2^3+3^3+.+n^3=(n^2*(n+1)^2)/41^3+2^3+3^3+.+100^3=(100^2*101^2)/4=25502500
原式=2x2y+2xy-3x2y-3xy-4x2y=-5x2y-xy当x=-2,y=12时,原式=-9.
原式=(4x2y+5xy2+3x-2y+5)-2(2x2y-3xy2-2x+1)=4x2y+5xy2+3x-2y+5-4x2y+6xy2+4x-2=11xy2+7x-2y+3.
(2x3-3x2y-2xy2)-(x3-2xy2+y3)+(-x3+3x2y-y3)=2x3-3x2y-2xy2-x3+2xy2-y3-x3+3x2y-y3=-2y3=-2×(-1)3=2.因为化简的
x=2013,y=2013[3x(x²y-xy²)+xy×(3xy-2x²)]/(x²y)=[3x²y(x-y)+x²y×(3y-2x)]/
根据题意得:(x3-3x2y)-(3x2y-3xy2)=x3-3x2y-3x2y+3xy2=x3-6x2y+3xy2,故选C.
(1)(x3-2x2y+3y2)-(-2x3-3x2y+5y2)=x3-2x2y+3y2+2x3+3x2y-5y2=3x3+x2y-2y2,答:这个多项式为3x3+x2y-2y2.(2)当x=-12,
答案:2x^2y+2xy^2原式=4x2y-{x2y-[3xy2-2x2y+4xy2+x2y]}-5xy2=4x2y-{x2y-[7xy2-x2y]}-5xy2=4x2y-{x2y-7xy+x2y]}
(2x2y-xy2)-(x2y-3xy2)=2x2y-xy2-x2y+3xy2=x2y+2xy2.故选C.
根据题意得,算式为:-3x2-[-4x2y+(-5x2)+2x2y],-3x2-[-4x2y+(-5x2)+2x2y]=-3x2+4x2y+5x2-2x2y=2x2+2x2y=2x2(1+y).
原式=5xy2-2x2y+3xy2-2x2y=8xy2-4x2y,∵(x-2)2+|y+1|=0,∴x-2=0,y+1=0,即x=2,y=-1,则原式=16+16=32.
x=±1,y=±3,z=±2xyzz>y则0>x>z>yx=-1,y=-3,z=-2,x2y-[4x2y-(xyz-x2z)-3x2z]-2xyx=x2y-4x2y+xyz-x2z+3x2z-2xyx
代入x=-1,y=1,2x^y-(5xy^-3x^y)-x^=2*(-1)^*1-{5*(-1)*1^-3*(-1)^*1}-(-1)^=2-(-5-3)-1=9备注:2^表示2的平方
5x2y+3x2y+(-4x2y)=(5+3-4)x2y=4x2y,故答案为:4x2y.
原式=-xy(x-y),当x-y=3,xy=-2时,则原式=-3×(-2)=6.故答案为:6.
2的立方+3的立方+4的立方+5的立方.+98的立方+100的立方=[(1+100)*100/2]^2-1=5050^2-1=25502799
解3xy²-[2xy²-2(xy-1.5x²y)]+xy-3x²y=3xy²-(2xy²-2xy+3x²y)+xy-3x²
5x2y+3x2y2+(-4xy2)=5x2y+3x2y2-4xy2.