`1) x/6=y/5=z/3=(x+y-z)/(6+5-3)`
`=54/9`
`=6`
`=>`
`x=6.6=36`
`y=6.5=30`
`z=6.3=18`
Vậy `x=36; y=30; z=18`
`2)`
`x/2=y/3 => x/8=y/12`
`y/4=z/5 => y/12=z/15`
`=> x/8=y/12=z/15=(x+y-z)/(8+12-15)`
`=25/5`
`=5`
`=>`
`x=5.8=40`
`y=5.12=60`
`z=5.15=75`
Vậy `x=40, y=60, z=75`
`3) x/2=y/3=z/4=(x+2y-3z)/(2+2.3+3.4)`
`=-20/20`
`=-1`
`=> `
`x=(-1).2=-2`
`y=(-1).3=-3`
`z=(-1).4=-4`
Vậy `x=-2; y=-3; z=-4`
`4) x/2=y/3=z/5=(2x+3y+5z)/(2.2+3.3+5.5)`
`=76/38`
`=2`
`=>`
`x=2.2=4`
`y=2.3=6`
`z=2.5=10`
Vậy `x=4; y=6; z=10`
