1,已知1/x + 1/y = 1/(x+y)
1.已知1/x+1/y=-1/x+y,则y/x+x/y=?
已知4x=9y求(1)x+y/y (2)y-x/2x
已知y=1x
已知函数Y=-x+1,(x
已知x+y=1,xy=-二分之一,求x(x+y)(x-y)-x(x+y)²
已知x,y满足约束条件:x-y+1>=0,x+y-2>=0,x
已知x=1/3,y=-1/2,求代数式x-(x+y)+(x+2y)-(x+3y)+(x+4y)-(x+5y)+...-(
已知:3x=8y.求(1)x+y/y (2)2x+3y/x-2y
一条分式数学题已知x y z满足x/x+y + y/z+x + z/x+y =1,求x²/x+y + y&su
已知x²+y²+5=2x+4y,求【2x²-(x-y)(x-y)】【(x+y-1)(x-y
已知实数x,y满足方程x*x+y*y-4x+1=0.求y-x的最大值
已知x=2+根号3,y=2-根号3,计算代数式(x+y/x-y-x-y/x+y)乘以(1/x^2-1/y^2)