jika f (2) = 5 dan f (5) = 8 tentukan a. Nilai fungsi f (x) = ax + b b. Nilai f (10)

jawab

f(x)= ax + b
f(2) = 5 → 2a + b = 5 ..(i)
f(5) = 8 → 5a + b = 8 ..(ii) ..(-)
-3a =- 3
a = 1
b = 5 - 2a  → b = 5 -2(1) = 3

f(x)= x + 3
f(10) = 10 + 3
f(10) = 13