Dik fungsi f(x)=3x + y dan f(-1)=12. Pertanyaan: f(5)-f(2)= Toolong secepatnya y bosss

f(x) = 3x + y
f(-1) = 3.-1 + y =12
-3 + y = 12
y = 12 + 3
y = 15

f(5) = 3.5 + 15
= 15 + 15
= 30

f(2) = 3.2 + 15
= 6 + 15
= 21

f(5) - f(2) = 30 - 21 = 9