a + b + c = 84,5
a = b + 3,5
c = 5×b
inlocuim in prima relatie in functie de b
b + 3,5 + b + 5×b = 84,5
7 × b = 84,5 - 3,5
7 × b = 81
b = 81/7
a = 81/7 + 3,5 = 81/7 + 35/10 = (810 + 245)/70 = 1055/70 = 211/14
c = 5 × 81/7 = 405/7
a = 211/14
b =81/7
c = 405/7
Verificam:
211/14 + 81/7 + 405/7 =
= (211 + 81×2 + 2×405)/14 =
= (211 + 162 + 810)/14 =
= 1183/14 =
= 84,5
