Answer:
2 < x < 18
Step-by-step explanation:
The sum of the shorter two sides of a triangle must be greater than the longest side.
If 10 is the longest side:
x + 8 > 10
x > 2
If x is the longest side:
8 + 10 > x
18 > x
The length of the third side must be greater than 2 and less than 18.
