已知2x-3y=5,4x^2-9y^2=55,求x,y
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)
已知4x=9y求(1)x+y/y (2)y-x/2x
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X-Y/X+Y=3,求代数式2(x-y)/X+Y-3X+Y/X+Y
已知X.x+y.y-4x+2y+5=0,求4X.X-12X Y+9Y.y的值
已知x/y=3/2求代数式4x-9y/2x+3y
已知x,y>0 2x+y+3=xy 求5x+4y最小值
已知x²+y²+5=2x+4y,求【2x²-(x-y)(x-y)】【(x+y-1)(x-y
1.已知:x-2y=3,求[(3x+2y)(3x-2y)-(x+2y)(5x-2y)]除4x 的值
已知x-2y=2011,求[(3x+2y)(3x-2y)-(x+2y)(5x-2y)]÷4x的值.
已知2x-y=10,求[(x²+y²)-(x-y)²+2y(x-y)]/4y
已知x/y=2,求2x(x+y)-y(x+y)/4x²-4xy+y²