x:y:z=1:3:5

{x+y+z=1;x+3y+7z=-1;z+5y+8z=-2 3x+2y+z=14 ,x+y+z=10,z+2x+3y=1 5 x+y+z=2 x-3y+2z=1 2x+2y+z+5 要具体步骤.. X+Y+Z=200,1/3X+4Y+5Z=200,求X,Y,Z等于多少? x:y:z=1:3:5 x-y-z=-1 3x+5y+7z=11 4x-y+2z=-1 分别求出x=?y=?z=? x,y,z属于正实数,且3x+4y+5z=1 求1/(x+y)+1/(y+z)+1/(x+z)的最小值 已知x:：y：z=3：4：5,(1)求x+y分之z的值；（2）若x+y+z=6,求x,y,z. x/2=y/3=z/5 x+3y-z/x-3y+z {5x-3y+z=2{5x+2y-4z=3{-5x+y-z=2 {x-y-z=-1{3x+5y+7z{4x-y+2x=- 已知x:y:z=4:5:7,求:(1)2x+3y+z/5z; (2)x+y/y+z. 解方程一;{x+y-z=6,x-3y+2z=1,3x+2y-z=-7.②{3x+4z=7,2x+3y+z=9,5x-9y