diketahui f(x)=ax+b dengan f(2)=8 dan f(4)=14,tentukan nilai f(0)- f(3)

f(x) = ax + b

f(2) = 2a + b
8 = 2a + b....... (1)
f(4) = 4a + b
14 = 4a + b......(2)

eliminasi (1) (2)

2a + b = 8
4a + b = 14
________-
-2a = -6
a = -6 : -2
a = 3
Substitusi a = 3 ke persamaan (1)
2a + b = 8
2(3) + b = 8
6 + b = 8
b = 8 - 6
b = 2

Untuk fungsinya f(x) = 3x + 2

Ditanyakan f(0) - f(3)
f(0) = 3(0) + 2 = 2
f(3) = 3(3) + 2 = 11

Sehingga f(0) - f(3) = 2 - 11 = -9