The sum of the lengths of any two sides of a triangle must be greater than to the length of the third side.
x - third side
if x ≤ 16 < 17 or 16 ≤ x < 17 then
x + 16 > 17 |-16
x > 1
x ∈ (1; 16]
if 16 < 17 ≤ x then
16 + 17 > x
33 > x
x ∈ [17; 33)
Answer: x ∈ (1; 16] ∪ [17; 33) → 1 < x ≤ 16 or 17 ≤ x < 33
