fungsi f di tentukan dengan rumus: f(x) = ax +b. jika f(5) = 13 dan f(-2) = -8 maka nilai a dan b berturut - turut adalah..

f(x) = ax + b

f(5) = 13
f(5) = a(5) + b = 13
5a + b = 13

f(-2) = -8
f(-2) = a(-2) + b = -8
-2a + b = -8

* 5a + b = 13
-2a + b = -8
_______________ -
7a = 21
a = 3

* 5(3) + b = 13
15 + b = 13
b = -2

f(x) = 3x - 2