suatu fungsi g didefinisikan g(x) = 1/2x + 9. Jika g(a) =47, maka nilai a sama dengan

g(x) = 1/2x + 9
g(a) = 1/2a + 9
47 = 1/2 a + 9
47 - 9 = 1/2 a
38 = 1/2 a
38 ÷ 1/2 = a
38 × 2 = a
76 = a
a = 76

maka nilai a = 76