若,2011x^3+2012y^3+2013z^3的立方根=2011的立方根+2012的立方根+2013的立方根,2011x^3=2012y^3=2013z^3,xyz＞0,求1/x+1/y+1/z的值.（提示：设2011x^3=2012y^3=2013z^3=m,则,2011x^2=m/x,2011的立方根=m的立方根/x,同理可得2012

化简(2x^3y^3+x^4y^2+x^2y^4)^2-x^2y^2(x+y)^2,x=2012,y=-2011 若2x+y=2012,则代数式2(3x-2y)-(x-y)+(-x+9y)= 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 x+y/2+x-y/3=6,4(x+y)-3(x-y)=-20 {(x+y)/2+(x-y)/3=6 4(x+y)-3(x-y)=-20 4(x+y)-3(x-y)=-20,2/x+y+3/x-y=6 若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 (3x-y)(3y+x)-(x-y)(x+y) 若|x-3|=2,|y+1|=2,|x|大于|y|,xy小于0,且求（x+2y）的2012次方+（x+2y）的2011次方+...+（x+2y）的2次 若x、y互为相反数,则x+2x+3x+...100x+100y+99y+98y+...+y 若x,y为正整数,且满足3x(x+y)-y(x+y)=7,求x,y 若2x=3y,则(x*x+y*y)/x*x=? 若x:y=3则x:(x+y)= 先化简,再求值.2x(x+y)-(x+y)^2,其中x=根号2012,y=根号2011（2）a^2(x-y)-2a(x-y)^2+(x-y)^3 若3x=5y,则x:y=________,(x-y):y=______ x(x-y)2-(y-x)3 5x+3y+2z=2011 4x+6y+7z=2012 求x+y+z 若3x=7y,则y比x= ,x:（x+y）=