数学题--已知x+1/2=y+3/4=x+y/5,则3x+2y+1/x+2y+3=
已知x=1/3,y=-1/2,求代数式x-(x+y)+(x+2y)-(x+3y)+(x+4y)-(x+5y)+...-(
数学题--已知x+1/2=y+3/4=x+y/5,则3x+2y+1/x+2y+3=
数学题--已知x+1/2=y+3/4=x+y/5,则3x+2y+1/2x-y+3=?
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)
数学题……555{(3x+y)(3x-y)-(x-5y)(5x-y)-(x-2y)²÷(-4x),x=-2.y
问一条数学题:已知实数x、y满足√(2x-3y-1) + |x-2y+2|=0,求2x- 4/5y的值
先化简再求值(x-y)(x+y)-(x-2y) 的完全平方+x(3x-5y)-(x-y)(x-2y),其中x=1/2 y
化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1
已知X-Y/X+Y=3,求代数式2(x-y)/X+Y-3X+Y/X+Y
{3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1
已知:3x=8y.求(1)x+y/y (2)2x+3y/x-2y
(3x-2y)(4x-5y)-11(x+y)(x-y)+5xy,已知X=3又1/2,y=2又1/3