若(x-1/2x-3)^2+(3y+1/y-2)^2=0 求代数式(2/2x-1)-(3/6y+1)的值 急用,在线等.若(x-1/2x-3)^2+(3y+1/y-2)^2=0 求代数式(2/2x-1)-(3/6y+1)的值急用,在线等.回答的好加分.

若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 x²/xy-x/y 3x/4x+y - x-2y/4x+y (1-y/y+x)÷x/y²-x² 化简 3x(x^2-x-1)-(x+1)(3x^-x) X^3(x-y)+x(y-x) 若变量x,y满足约束条件{x>=-1;y>=x;3x+2y 若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 若x=-1/4,能否确定代数式(2x-y)(2x+y)+(2x-y)(y-4x)+2y(y-3x)的值? 若x+y=4,则多项式1/2(x+y)+4(x-y)-3（x-y）-3/2(x+y)-x+y值是（） (3x-y)^2+(3x+y)(3x-y),x=1,y=-2 (x-y)/(x+y)=3求( 3x-2y-1)/(x+y-5) 二元一次方程 ：2(x+y)-(x-y)=3 (x+y)-2(x-y)=1 2(x+y)-3(x-y)=1 6(x+y)+(x-y)=51 {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 变量x,y满足约束条件,x+y>=3,x-y>=-1,2x-y (Y-X)^3*(X-Y)^m+(X-Y) ^m+1*(Y-X)^2 (x-y)^2+(x+y)(x-y) 其中 X =3 Y=-1 函数,y=3x/(x^2+x+1) ,x 函数y=3x/(x^2+x+1) （x 1/(x-y)+1/(x+y)+2x/(x^2+y^2)+4x^3/(x^4+y^4)化简