1) 75=3*5*5
30=2*3*5
12=2*2*3
НОК (12,30,75)=2*2*3*5*5=300
2) 105=3*5*7
42=2*3*7
15=3*5
НОК (15,42,105)=2*3*5*7=210
3) 35=5*7
28=2*2*7
21=3*7
НОК (21,28,35)=3*2*2*5*7=420
1) 12 = 2*2*3
30 = 2*3*5
75 = 3*5*5
НОК = 2*2*3*5*5=300
2) 15 = 3*5
42 = 2*3*7
105 = 3*5*7
НОК = 2*3*5*7=210
3) 21 = 3*7
28 = 2*2*7
35 = 5*7
НОК = 2*2*3*5*7=420