Janelle S. answered 09/29/20
Penn State Grad for ME, Math & Test Prep Tutoring (10+ yrs experience)
Your question is missing which line segment has which length. I'm assuming it should be as follows (if not, you can use the same equation setup below with the correct line segment lengths):
AB = x + 6
BC = 3x - 5
AC = 37
AC = AB + BC
37 = (x + 6) + (3x - 5) = 4x + 1
4x = 36
x = 36 / 4 = 9