(2X-3Y):(X+Y)=1:2求 X:Y
已知:3x=8y.求(1)x+y/y (2)2x+3y/x-2y
已知x=3分之1,y=二分之一,求代数式x-(x+y)+(x+2y)-(x+3y)+...-(x+13y)的值
若|x+2y-1|+y²+4y+4=0,求(2x-y)²-2(2x-y)(x+2y)+(x+2y)&
若|x+y-1|+(x-y-2)²=0,求代数式(x+2y)(x-2y)-(2x-y)(-y-2x)的值.
x(x-1)-(x平方-y)=-3,求x平方+y平方-2xy
(1)已知x+y=6,x²-y²=5,求x-y的值(2)若x+y=3,x²+y²
已知X-Y/X+Y=3,求代数式2(x-y)/X+Y-3X+Y/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x/2=y/3=z/4,求下列各式 (1)(x+y+z)/x (2)(x-y+2x/(x-y-2z)
已知x²+|y+x|=x-1/4,求(3x+y)²(2x-y)²-(4x²+y&
(1)正数x,y满足x^2-y^2=2xy,求(x-y)/(x+y)
2x²-3xy=y²=0(x,y不得o)求x/y+y/x