F(x) = ax + b F(1) = -1 F(3) = 5 Tentukan f (x) ?

f(x) = ax+b

f(1)= a(1)+b
-1 = a + b

f(3) = a(3) + b
5 = 3a+b

3a+b=5
a+b=-1
________-
2a = 6
a= 3

3+b=-1
b= -4

f(x) = 3x - 4

f(x) = ax + b
f(1) = a(1) + b
=> a + b = -1................(persamaan 1)
f(3) = a(3) + b
=> 3a + b = 5................ (persamaan 2)

=> a + b = -1
    3a + b = 5 _
-2a = -6
a = -6/-2 = 3

Substitusi nilai a ke persamaan 1
a + b = -1
3 + b = -1
b = -1 - 3
= -4

f(x) = ax + b
jadi, f(x) = 3x - 4

Semoga bermanfaat ^_^