1)a=2;b=3
2)divizorii comuni sunt:1;3;2;3
3)X=7
4) multiplii comuni sunt:14;28;42.
5)x=0=>21x=210
6)xx=30,60,90
7)multiplii lui 17 mai mari ca 21 si mai mici ca 70 sunt:34,51,68
8)nr sunt:120,130,210,260,290,330,360,390,420,480,450,510,570,630,660,690,720,780,810,870,900,300,600,930,960,990.
9)nr sunt:1410,1420,1450,1460,1430,1440,1470,1480,1490