Jika f(2)=5 dan f(5)= 8 dengan rumus f(x) = ax+b, maka nilai f(10) adalah...

f(2) = 5
f(5) = 8

#f(x) = ax + b = c
f(2) = a(2) + b = 5
= 2a + b = 5 ... pers 1

#f(x) = ax + b = c
f(5) = a(5) + b = 8
= 5a + b = 8 ... pers 2

#Eliminasi pers 1 dan 2
2a + b = 5
5a + b = 8
_________ -
-3a + 0 = -3
-3a = -3
a = -3 / -3
a = 1

#subsitusi a = 1 ke pers 1
2a + b = 5
2(1) + b = 5
2 + b = 5
b = 5 - 2
b = 3

sehingga mempunyai nilai a = 1 dan b = 3 dan nilai linearnya adalah x + 3

f(x) = ax + b = c
f(10) = 1(10) + 3 = 0
= 10 + 3 = 0
= 13 = 0
= 0 = -13

hasil akhir menunjukan bahwa nilai f(10) = -13