You have to use the substitution method by substituting one Y value with the other
The answer should be:
20.875
Hope this helps.
Answer:
f(n)= 5 · 4
Step-by-step explanation:
You use the explicit formula for geometric sequence. The five is the firat term and is placed correctly. The 4 is the rate of change, because if you multiply 5 by 4 you get 20 and so on.