Let a, b, c be positive real number such that a b = b c = c a . Find the value of the expression: P = 4a + 6b + 2017c 4a − 6b + 2017c The entrance exam in grade 10, Bac Ninh gifted high school, 2017 We have a b = b c = c a = a + b + c b + c + a = 1 ⇒Let a, b, c be positive real number such that a b = b c = c a . Find the value of the expression: P = 4a + 6b + 2017c 4a − 6b + 2017c The entrance exam in grade 10, Bac Ninh gifted high school, 2017 We have a b = b c = c a = a + b + c b + c + a = 1 ⇒