1) 5x < 30
x < 30 : 5
x < 6
7x < 49
x < 49 : 7
x < 7
100x < 4900
x < 4900 : 100
x < 49
8x < 72
x < 72 : 8
x < 9
10x < 4200
x < 4200 : 10
x < 420
1000x < 32000
x < 32000 : 1000
x < 32
2) 5(x + 3) < 40
x + 3 < 40:5
x + 3 < 8
x + 3 ∈ {0, 1, 2, 3, 4, 5, 6, 7} daca vorbim de numere naturale
x < 8 - 3
x < 5
x ∈ {0, 1, 2, 3, 4} (numere naturale)
3) 7y - 35 < 35
7y < 35 + 35
7y < 70
y < 70 : 7
y < 10