Question

Helppppp .............

Answer 1

Ok so suppose the theory that if you add two sides of a triangle together it will be more than the remaining side but it has to work for all three sides so the two sides 10+8=18 so the number has to be less than 18 but the number also has to be more than 3 because 8+3=11 and 11 is larger than ten. the answer is
$3 \leqslant x \leqslant 17$