Răspunsuri

2014-10-16T16:29:15+03:00
2014-10-16T19:50:15+03:00
12 ≤ x - 3 ≤ 27   adunam 3 ⇒15 ≤ x ≤30 ⇒x∈{15,16,17.....29,30}