Answer:
8. and anything less
Explanation:
The line thing would be pointing to the left as 8 and lower fit the solutions.
8 - 4 = 4 which is less than 5
7 - 4 = 3 which is less than 5
6 - 4 = 2 which is less than 5
If you were to carry on testing these where X is getting smaller in value, it will never end. Any number above 8 will not work