m<20 =>
5m<100
Cum: 5m=15n ==> 15n<100
90<100<105, adica 15×6<100<15×7
15n<100 inseamna ca 15n <= 90 ==> n<=90:15 ==> n<=6
==> n€{1, 2, 3, 4, 5, 6}
15n€{15, 30, 45, 60, 75, 90}
Dar 15n=5m ==> 5m€{15, 30, 45, 60, 75, 90} ==>
m€{3, 6, 9, 12, 15, 18}
(n, m)€ {(1, 3) ; (2, 6) ; (3, 9) ; (4, 12) ; (5, 15) ; (6, 18)}
am notat cu
==> semnul rezulta
<= semnul mai mic sau egal
