Please help me with this question!

Which recursive formula can be used to determine the total amount of money earned in any year based on the amount earned in the previous year? f(n+1)=f(n)+5

What is the value of the expression i 0 × i 1 × i 2 × i 3 × i 4? 1 –1 i –i

I'm confused on how to solve the triangle. can someone me ?