Ta có `: 2x =` `4y = 8z` `=> x/(1/2)` `= y/(1/4)` `= z/(1/8)`

Đặt  `x/(1/2) =` `y/(1/4)` `= z/(1/8)` `= m`

`=>` `{(x = \frac{1}{2}m),(y = \frac{1}{4}m),(z = \frac{1}{8}m):}`

Mà `x . y` `. z = 8`

`=>` `1/2m . 1/4m` `. 1/8m = 8`

`=>` `1/64m^3 = 8`

`=>` `(1/4m)^3 = 2^3`

`=>` `1/4m = 2`

`=> m` `= 2 : 1/4`

`=>` `m = 8`

Với `m =` `8 =>` `{(x = 4),(y = 2),(z = 1):}`

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