Răspuns:
Explicație pas cu pas:
12+x > 18 => x > 18-12 => x > 6 => x ∈ (6 ; +∞)
7+6x < 2(5x-8) <=> 7+6x < 10x-16 =>
7+16 < 10x-6x => 23 < 4x <=> 4x > 23 => x > 23/4 =>
x ∈ (23/4 ; +∞)