diketahui fungsi f(x) = ax+b. jika f(2) = -2 dan f(3) = 13 tentukan nilai f(4)

f(x) = ax + b
f(2) = a(2) + b = - 2
f(3) = a(3) + b = 13
..
2a + b = - 2
3a + b = 1
-------------- --
- a = - 3
a = 3

2a + b = - 2
2(3) + b = - 2
6 + b = - 2
b = - 2 - 6
b = - 8

bentuk fungsi yang baru
f(x) = ax + b
f(x) = 3x - 8

f(4) = 3(4) - 8
= 12 - 8
= 4

jadi nilai f(4) = 4