Suatu fungsi dirumuskan dengan fx = ax + b. Jika F(-2) = 14 dan F(3) =-1 maka nilai F(1) adalah

Jawab :

f(x) = ax + b
f(-2) = a(-2) + b = -2a + b = 14
f(3) = a(3) + b = 3a + b = -1

-2a + b = 14
3a + b = -1
___________ -
-5a = 15
a = -3

3a + b = -1
3(-3) + b = -1
-9 + b = -1
b = -1 + 9
b = 8

f(x) = ax + b = -3x + 8

Nilai f(1) = -3(1) + 8 = -3 + 8 = 5