Caranya ya Please :v

f(a) = (a^2 + 2) / a + 3
6 = (a^2 + 2) / a + 3
6(a + 3) = a^2 + 2
6a + 18 = a^2 + 2
a^2 - 6a + 2 - 18 = 0
a^2 - 6a - 16 = 0
(a - 8) (a + 2) = 0
a = 8 atau a = -2

karna a > 0 maka,
a = 8