Suatu fungsi dirumuskan dengan f(x) = ax + b. Jika f(-3) = -7 dan f(2) 0= 13 ,nilai f(5) adalah

f(x) = ax + b

Jika:
f(-3) = -7
f(-3) = a.(-3) + b = 7
f(-3) = -3a + b = 7
b = 7 + 3a

Jika :
f(2) = 13
f(2) = a.2 + b = 13
f(2) = 2a + b = 13
2a + b = 13

Maka, Jika b = 7 + 3a maka,
2a + ( 7 + 3a ) = 13
2a + 3a = 13 - 7
5a = 6
a = 6/5