please give me formula how to find roi

Complete the Table below. Fill in the values of A-Z and i-vi. Discount rate 12% Project Year 1 Year 2 Year 3 Year 4 Year 5 Total Costs $5,000 $2,000 $2,000 $2,000 $2,000 F Discount factor A B D E Discount costs G H | J K L. Benefits $1,000 $2,000 $4,000 $6,000 $8,000 R Discount factor M N 0 Q Discount Benefits S T U V w Cash flow i ii iii iv V vi NPV Y ROI Z