Suatu fungsi dirumuskan f(x) =ax+b jika f(-2)=14 dan f(3)=-1,nilai f(7) adalah

f(-2) = -2a + b
14= -2a + b

f(3) = 3a + b
-1 = 3a + b

*eliminasikan

15 = -5a
a = -3 , b = 8

maka ,
f(7) = -3(7) + 8
= -21 + 8 = -13

f(x) = ax + b

f(-2) = 14
a.(-2) + b = 14
-2a + b = 14.....(1)

f(3) = -1
a.3 + b = -1
3a + b = -1.......(2)

(2) dan (1) eliminasi
3a + b = -1
-2a + b = 14
------------------ --
5a = -15
a = -15/5
a = -3

a = -3 subtitusi ke (1)
-2a + b = 14
-2.(-3) + b = 14
6 + b = 14
b = 14 - 6
b = 8

f(x) = -3x + 8
f(7) = -3.7 + 8
f(7) = -21 + 8 = -13


Moga membantu...