Need help with my math

Question

One side of a triangle is one third the longest side.the third side is 8 feet less than the longest side.the perimeter is 104.find all three sides

Answer 1

S=L/3, X=L-8

S+L+X = 104

L/3 + L + L-8 = 108

7L/3 = 116

7L = 348

L = 348/7 = 49 5/7

X=L-8 = 41 5/7

S= L/3 = 348/7 x 1/3 = 116/7 = 16 4/7

49 5/7 + 41 5/7 + 16 4/7 = 106 14/7 = 108 feet