3x+4y+5z=12急求
1.已知x:y:z=4:5:7,求:(一)2x+3y+z/5z; (二)x+y/y+z 非常急,
已知x/3=y/5=z/4,求x+y+z/y和x+y-z/y-x的值,2种方法.急等.
200分求数学题,急x+y-z=-14x-3y+2z=162x-2y-3z=5求z等于多少
x=y/z=z/3,x+y+z =12,求2x+3y+4z是多少,
急··已知x/3=y/5=z/7,求(x+z-y)/y和(2x+3y+4z)/(5x-3y+z)
已知3X=4X,5Y=6Z求X+Y:Y+Z
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.
已知5x=3y,4z=7y,求x:y:z
已知3x=4y,2y=5z,试求x:y:z
x/3=y/4=z/5求x-y+z/y
3x=4y 2y=5z 试求x:y:z
已知x:y:z=3:4:5,3x+2y-4z=18.求:x+y+z.