4) D18={1,2,3,6,9}
D45={1,3,5,9}
D105={1,3,5,7,15,21,35}
D24={1,2,3,4,6,8,12}
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18=2×3la2
24=2la3×3
c.m.m.d.c=2×3=6
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45=3la2×7
105=3×5×7
c.m.m.d.c=3×5=15
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Divizorii comuni lui a si b (18 si 24)={1,2,3,6}
Divizorii comuni lui a si b (105 si 45)={1,3,5}
