Using the triangle inequality theorem, we can form these inequalities:
8 + 8.8 > x
8 + x > 8.8
x + 8.8 > 8
We technically don't need the third one, because we already know that x is greater than -0.8. (because lengthes can't be negative)
8 + 8.8 > x
8 + x > 8.8
We now need to isolate the "x" in the second inequality:
x > 8.8 - 8
x > 0.8
Here is what we now know about x:
x < 16.8
x > 0.8
Therefore, the range for x is: {x | 0.8 < x < 16.8 }
EXTRA KNOWLEDGE:
This is not needed, but the range in interval notation form is (0.8, 16.8)
EDIT: Sorry, I used the wrong numbers!
:)