Answer
I think you just draw a line from 9 to 4, i'm not so sure tho.
Step-by-step explanation:
*Snarls at my own stupidity*
Answer:
f(x) =1/3 × 4^x
f(4) = 1/3 × 4⁴
= 1/3 × 256
= 256/3
Hope this helps