Salut!
Răspuns:
b =7a / 5
a + 7a / 5 + 1 = a + 7a / 5 × 5/7a + 10
5a / 5 + 7a / 5 + 5 / 5 = 35a² + 35a / 35a + 350a / 35a
35a² + 49a² + 35a = 35a² + 385a
49a² - 350a = 0
7a × ( 7a - 50 ) = 0
7a = 0 → a = 0
7a = 50
a = 50 / 7
b = 7 × 0/5
b = 0
b = 7 × 50/7
b = 50
Succes!