`Bài 3.` `Cho 3` `số : a = 40; b = 75; c = 105`
`a, Tìm` `ƯCLN(a, b, c)=ƯCLN(40,75,105)`
`40=2^3.5`
`75=3.5^2`
`105=3.5.7`
`->ƯCLN(40,75,105)=5`
`b, Tìm` `BCN``N(a, b, c)=BCN``N(40,75,105)`
`40=2^3.5`
`75=3.5^2`
`105=3.5.7`
`->BCN``N(40,75,105)=2^5.``5².3.7=4200`