Question

3[15-(x-1)×2]+5>sau egal20

Answer 1

3[15-(x-1)*2]+5≥20
3[15-(x-1)*2]≥ 15
15-(x-1)*2≥ 5
-(x-1)*2≥ -10 / *(-1)
(x-1)*2≤10
x-1≤5
x≤6
x e {0,1,2,3,4,5,6}