F(x) = ax + b jika f (1) = 15 dan f(5) = 14 tentukan nilai a dan b

f(x) = ax + b
f(1) = 15 》a.1 + b = 15 => 1a + b = 15
f(5) = 14 》a.5 + b = 14 => 5a + b = 14

Eliminasi :
1a + b = 15
5a + b = 14
----------------- -
-4a + 0 = 1
-4a = 1
a = 1 : -4
a = -0,25

Subtitusi :
a = -0,25
1a + b = 15
1.-0,25 + b = 15
-0,25 + b = 15
b = 15 + 0,25
b = 15,25