f(x)=ax + b dengan nilai f(-2)= -1 dan f(1)=11. nilai 5a + b=?

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

pakai metode eliminasi campuran
-1 = -2a + b
11 = a + b
----------------- -
-12 = -3a
a = 4

11 = a + b
11 = 4 + b
b = 11 - 4
b = 7

5a + b
= 5 (4) + 7
= 27

maaf kalau salah :D

f(x) = ax + b

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

f(1) = a (1) + b = 11
a + b = 11
<=> a = -b + 11

-2a + b = -1
-2 (-b + 11) + b = -1
2b -22 + b = -1
3b = -1 + 22 = 21
b = 21/3 = 7

a = -b + 11
= -7 + 11
= 4

5a+b = 5(4) + 7 = 20 + 7 = 27