maka nilai f(–3) adalah....

Metode eliminasi
f(-2) = -2a+b = 13
f(3) = 3a+b = -7
-------------------------- -
-5a = 20
a = 20/-5
a = -4

Metode Subsitusi
a=-4 => 3a+b = -7
3(-4)+b = -7
-12+b = -7
b = -7+12
b = 5

Jadi, f(-3) = -3(-4)+5
= 12+5
= 17