Fungsi f dinyatakan dgn rumus f(x)=ax + b , jika f(0)=4 dan f(2)=10. Tentukan nilai f(9)

f(x) = ax + b
f(0) = 4
f(2) = 10

f(9) = ?

f(0) = a(0) + b = 4
b = 4

f(2) = a(2) + 4 = 10
2a + 4 = 10
2a = 10-4
2a = 6
a = 3

f(9) = ?
3 (9) + 4 =
27 + 4 = 31