已知1/x-1/y=3,则{2x-14xy-2y}/{x-2xy-y}的值为多少

已知(1/X )-(1/Y)=1,则(2X+3X-2Y)/(X-2XY-Y)=? 已知2x 十3y-1=y-x-8=x+6则2x-y= 速, 已知x^2-2=y,则x(x-3y)+y(3x-1)-2的值是, 已知|x+3|+(x+2y-1)平方=0,则x+y=? 1 已知1/X+1/Y=1/X+Y 则 Y/X+X/Y=2 已知1/X-1/Y=5,则3X+5XY-3Y/X-3XY-Y= 已知：2x+y=6,x-3y=1 求7y(x-3y)(x-3y)-2(3y-x)(3y-x) 已知x(x+1)-(x²+y)=3求2/x²+y²-xy 已知x-y=1,求[(x+2y)^2+(2x+y)(x-4y)-3(x+y)(x-y)]除以y的值大神们帮帮忙 已知x-y=1,求[(x+2y)²+(2x+y)(x-4y)-3(x+y)(x-y)]÷y的值 已知1/x-1/y=3,则代数式x(2-7y)-y(7x+2)/x(1-y)-y(x+1)的值为多少. 已知x+y+2(-x-y+1)=3(1-y-x)-4(y+x-1),则x+y等于多少 已知6x^2-7xy-3y^2+14x+y+a=(2x-3y+b)(3x+y+1),则a=?,b=? 已知x+y=a,2x-y=-2a,求[（x/y-y/x)/(x+y)-x(1/x-1/y)]/[(x+1)/y]的值 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) 已知1/x-1/y=3,则5x+3y-5y/x-2xy-y的值 已知x/1-y/1=3,则5x+xy-5y/x+2y-y的值为 已知,x(x+1)-(x^2+y)=3则x^2+y^2/2-xy= 已知(x+y)^2-2x+2y+1=0,则(x+y)^999=