`b)`
`(x-1)/3` = `(y-2)/4` = `(z-3)/5` và `x+y+z = 42`
`(x-1)/3` = `(y-2)/4` = `(z-3)/5` = `(x+y+z)/(3+4+5)`
= `42/12`
= `7/2`
Ta có `:`
`(x-1)/3` = `7/2` `⇒` `x` = `7/(2.3)` + `1` = `11,5`
`(y-2)/4` = `7/2` `⇒` `y` = `7/(2.4)` + `2` = `16`
`(z-3)/5` = `7/2` `⇒` `x` = `7/(2.5)` + `3` = `20,5`
`c)`
`(x+1)/3` = `(y+2)/-4` = `(z-3)/5` và `5x+y+2z=41`
`(x+1)/3` = `(y+2)/-4` = `(z-3)/5` = `(5x+y+2z)/[5.3+(-4)+2.5]`
= `41/21`
`(x+1)/3` = `41/21` `⇒` `x` =`41/(21.3)` - `1`
= `34/7`
`(y+2)/-4` = `41/21` `⇒` `y` = `41/[21.(-4)]` - `2`
= `-206/21`
`(z-3)/5` = `41/21` `⇒` `z` = `41/(21.5)` + `3`
= `268/21`
`d)`
`(x+1)/111` = `(y+2)/222` = `(z+3)/333` và `(3x+2y+z)/(3.111+2.222+333)`
= `1100/1110`
= `110/111`
`(x+1)/111` = `110/111` `⇒` `x` = `110/(111.111)` - `1`
= `109`
`(y+2)/222` = `110/111` `⇒` `y` = `110/(111.222)` - `2`
= `218`
`(z+3)/333` = `110/111` `⇒` `z` = `110/(111.333)` - `3`
= `327`
