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

dik :
f(x) = ax + b
f(-2) = 14
f(3) = -1
dit : f(7)???
f(-2) = > -2a + b = 14
f(3) = > 3a + b = -1
---------------------- -
5a = 15
a= 3
f(-2) => -2a + b = 14
-2 (3) + b = 14
-6 + b = 14
b = 14 + 6
b = 20
f(x) = 3a + 20
f(7) = 3(7) + 20
f(7)= 21 + 20
f(7) = 41

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

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

-2a+b =14
2a+b = -1 dijumlahkan
a = 13

a=13
-2.a+b =14
-2.13 + b =14
-26 +b =14
b =14 +26
b = 40

f (x) = 13.x+40
f (7) = 13.7+40
f (7) = 91 +40
f (7) = 131