suatu fungsi dirumuskan f(x) = ax + b. jika f(-2) = 13 dan f(3) = -7, maka nilai f(-30) adalah

f(x) = ax + b
f(-2) = - 2a + b = 13
f(3) = 3a + b = -7
----------------------------(-)
- 5a = 20
a = - 4
3a + b = - 7
3(4) + b = - 7
b = - 7 - 12
b = - 19
f(x) = - 4x - 19

f(-30) = - 4(-30) - 19
= 120 - 19
= 101