Question 332726
Find all positive integers x for which it is possible for 2x + 3, 3x + 8, and
6x + 7 to be side  lengths of a triangle.

Every side should be lower than the sum of both others :

2x+3<3x+8+6x+7=9x+15 => x>-12/7=-60/35
3x+8<2x+3+6x+7=8x+10 => x>-2/5=-14/35
6x+7<5x+11 => x<4

hence x in [-2/5;+4]