What’s this answer ?

Answer:
12
Step-by-step explanation:
The average rate of change for f(x) in the closed interval [ a, b ] is
[tex]\frac{f(b)-f(a)}{b-a}[/tex]
Here [ a, b ] = [ 1, 3 ] , then
f(b) = f(3) = 27 ← value of y from table for x = 3
f(a) = f(1) = 3 ← value of y from table for x = 1
average rate of change = [tex]\frac{27-3}{3-1}[/tex] = [tex]\frac{24}{2}[/tex] = 12