已知：x+y=0.2,x+3y=1,则3x^2+12xy+12y^2的值位————

已知x/5=y/3,则(x/x+y)+(y/x-y)-(yxy/xxx-yxy) 已知:3x-5y=0,求x/y,x-y/y,x-y/x 已知x,y满足x+3y=5,3x+y=-1,则x-y=? 已知实数x,y,满足x-√x-1=√y+3-y,则x+y最大值是? 已知2x=3y,则y分之x=< >,y分之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：2x+y=6,x-3y=1 求7y(x-3y)(x-3y)-2(3y-x)(3y-x) 已知x-y=1,求[(x+2y)²+(2x+y)(x-4y)-3(x+y)(x-y)]÷y的值 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3X=5Y,则X:Y= 已知3x=8y,则x;y=? 已知|x+y-3|+(x-y)2=0则 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 比例线段：已知x/y=2/3,则 x/x+y= ,x-y/x+y= 要过程! 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