Diketahui f(x)=ax+b.jika f(3)=4 dan f(4)=8,maka f(12) adalah

F(3) => 3a + b = 4
f(4) => 4a + b = 8
Eliminasi b
-a = -4
a = 4

3(4) + b = 4
12 + b = 4
b = -8

f(12) => 4(12) + (-8)
=> 48 + (-8)
=> 40