Answer:
7 < x < 17
Step-by-step explanation:
Given 2 sides of a triangle then the third side x is in the range
difference of sides < x < sum of sides , then
12 - 5 < x < 12 + 5 , that is
7 < x < 17
The 3rd side could be 8, 9, 10, 11, 12, 13, 14, 15, 16