suatu fungsi memetakan x ke ax+b jika f(2)=8 dan f(5)=17

f(x) = ax + b

f(2) = 2a + b = 8
f(5) = 5a + b = 17
       ------------------- (-)
           3a = 9
             a = 3

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

jadi rumus fungsi f adalah
f(x) = 3x + 2

F(2) = 8.. a.8+b= 8 → 8a+b=8..(1)
F(5)=17.. a.5+b= 17 → 5a+b=17..(2)
_______ -
→3a = -9... a=9/3.. a=3
→8a+b=8..
8.3+b=8
24+b=8
B=8/24
= -3

Rumus fungsi : f(x) = 3(x)-3