\(\text{#3107.101107}\)
Ta có:
$12 = 3 \cdot 2^2$
$15 = 3 \cdot 5$
$18 = 3^2 \cdot 2$
$\Rightarrow$ ƯC`(12; 15; 18) = 3`
Vậy, ƯC`(12; 15; 18) = 3.`
12 = 22 x 3
15 = 3 x 5
18 = 2 x 32
ƯCLN ( 12,15,18 ) = 2 x 3 = 6
ƯC ( 12,15,18 ) = Ư(6) = ( 1;2;3;6)