suatu fungsi dengan rumus f(x)=ax+b. Jika f(2) =13 dan f(5)=22 maka f(-3)adalah

f(2) = ax+b
13 = a(2) + b
13 = 2a + b ...(i)

f(5) = ax+b
22 = a(5) + b
22 = 5a + b ...(ii)

Eliminasikan
2a + b = 13
5a + b = 22
_________ -
-3a = -9
a = 3

Substitusikan a = 3
2a + b = 13
2(3) + b = 13
b = 13 - 6
b = 7

Jadi a = 3 b = 7
f(-3) = ax + b
= 3.(-3) + 7
= -9 + 7
f(-3) = -2