sebuah fungsi f dinyatakan dengan rumus f(x) = ax + b . jika f ( 1 ) = - 1 dan f ( 2 ) = 5 , Nilai dari f ( 5 ) + 3 = ........? tolong dibantu ya ....

pers. ke 1
f(1) = -1
a(1)+b= -1
a + b = -1

pers. ke 2
f(2) = 5
a(2) + b = 5
2a + b = 5

lalu di eliminasi dan substitusikan
a+b =-1
2a + b = 5 (dikurangkan)
-a = -6
a = 6

cari b
a +b = -1
6 + b = -1
b = -7

nilai f(5) +3
= 6(5)+(-7) +3
= 26

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

f(2) = 5
f(x) = a(2) + b = 5a + b = 5

ELIMINASI
a+b = -1
2a + b = 5
---------------- --
-a = -6
a = 6

6 + b = -1
6 + 1 = -b
7 = -b
b = -7

f(5) = 6(5) + (-7)
= 30 - 7
= 23

f(5) + 3 = 23 + 3 = 26

Jadi, nilai dari f(5) + 3 = 26