设涵数y=|x-4|+|x-3|.求：(1)y的最小值；(2)使y=a恒成立的a的最大值

x/3=y/4,求(x*x-xy)/(x*x+y*y)的值 x(x-3y)=4y(x-3y),求x:y 已知2y-x=-3,求[4y(2x-y)-2x(2x-y)]/(2x-y 若(-x+6):(x-y):(4x+y)=3:14:1,求x+y 若(-x+6):(x-y):(4x+y)=3:14:1,求x+y (-x+6):(x-y);(4x+y)=3;14:1,求x+y的值. 已知:3x-5y=0,求x/y,x-y/y,x-y/x 已知x=3分之一,y=-2分之一,求代数式x-(x+y)+(x+2Y)-(x+3y)+(x+4y)...-(x+2009y) 求函数y=(3x+4)/(x-2) (x 求值域 1,y=(x+2)/(x*x+3x+6) 2,y=3x/(x*x+4) 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 /x/=3 /y/=4求x＋y X:2.5=Y:3/4 求X:Y 急 已知(x+2y)(2x-3y)=y(y-4x),试求x/y的值 已知X=2,求代数式,（2X-Y)(2X+Y)+(2X-Y)(Y-4X)+2X(Y-3X) 已知（x+y）2 =2,(x-y)3 =3,求(x+y)7(x-y)2(x+y)3(y-x)4 的值 已知2x-y/x+3y=2,求代数式4x-2y/x+3y减4x+12y除以2x-y