i cant seem to find what the total interest paid over life formula is

Paste Tge D35 XV A B E G 1 P APR PMT 2 $ 15,000.00 6 % 12 5 $ 289.99 4 Table Showing Monthly Payments for Different APR's and Terms Number of Years (t) APR 1,256.78 $ 1,263.58 $638.10 $ 1,270.41 $644.72 1,277.25 $ 7 1% $ 631.53 423.12 318.92 S256.41 $ 214.73 2% S 429.64 325.43 S 262.92 $ 221.26 3 % $ 436.22 S 332.01 S 269.53 S 227.91 442.86 S 449.56 S 10 4% $ 651.37 S 338.69 $ 276.25 $ 234.68 345.44 $ 1,284.11 S 1,291.00 $ 658.07 283.07 S 241.57 5% S 6% $ 11 12 664.81 456.33 S 352.28 S 289.99 S248.59 13 7% S 1,297.90 671.59 S 463.16 S 359.19 S 297.02 S 255.74 8% S 1,304.83 S 678.41 S 470.05 S 366.19 S 304.15 $ 263.00 14 477.00 S 373.28 S 311.38 270.38 1,311.77 $ 1,318.74 S 15 9% $ 685.27 S 16 10%| S 692.17 S 484.01 380.44 S 318.71 277.89 17 18 Total Interest Paid Over Life of the Loan 19 Number of Years (t) 6 20 APR 2 21 1% S 81.37 22 2% $ 23 3% S 24 4% $ 81.37 1,311.77 $ 685.27 1,318.74 $ 692.17 $ 9% $ 477.00 $ 373.28 $ 311.38 270.38 10% $ 484.01 380.44 $ 318.71 $ 277.89 Total Interest Paid Over Life of the Loan Number of Years(t) APR 1% $ 81.37 2% $ 3% 4% $ 81.37 5% $ 6% $1,579,498.92 7% $1,588,047.34 8% $1,596,621.69 9% $1,605,221 10% $1,613,848.07 1,256.78 5 b.) Create another table which computes the total interest paid over the life of the loan for each of the sixty monthly payments given in the table. There is a very easy way to do this, simply subtract the loan from the total of all the payments made over the life of the loan. Be sure to use proper absolute/mixed/relative cell references. c.) Create a well-labeled graph for your table from part b