dik : f : R --> R , g : r --> R fungsi f(x) = 5x - 2 g(x) = 3x + a tent. Nilai a agar (fog)(x) = (gof)(x)

fog(x) = gof(x)
f(g(x)) = g(f(x))
5(3x + a) - 2 = 3(5x - 2) + a
15x + 5a - 10 = 15x - 6 + a
coret 15x
5a - 10 = a - 6
5a - a = -6 + 10
4a = 4
a = 1