suatu fungsi linier dirumuskan sebagai f(X)=ax+b.jika [tex]f(2) = 1 \: dan \: f(5) = 8 \: [/tex] maka nilai dari [tex]f(10) = [/tex]

Jawab :
f(x) = ax + b
f(2) = 2a + b = 1........ (x5)
f(5) = 5a + b = 8....... (x2)
10a + 5b = 5
10a + 2b = 16
-------------------- -
3b = -11
b = -11/3

2a + b = 1
2a + (-11/3) = 1
2a = 1 - 11/3
2a = -8/3
a = (-8/3)/2
a = -4/3

f(10) = 10.(-4/3) + (-11/3)
f(10) = (-40/3)+(-11/3)
f(10) = -51/3