Question

Am nevoie de ajutor rapid , va rog
Aflați elementele mulțimii A={x€N | 15<2x-7<31

Answer 1

15<2x-7<31/+7
22<2x<38/÷2
11<x<19⇒x∈{12, 13, 14, 15, 16, 17, 18}
⇒A={12, 13, 14, 15, 16, 17, 18}

Answer 2

15<2x-7<31 I +7
22<2x <38  I  :2
11<X< 19 =>  X apartine { 12,13,14,15,16,17,18}