Uhhh. Help me pleaaasse

65 8 7 4 5 6 8 4 3 2 1 9 5 6 4 2 1 6 5 1 5 1 3 2 3 5 multiply the third number in the first row by the seventh number in the third row. add this result to the fifth number in the second row. add to this total ten times the fourth number in the third row. subtract the eighth number in the first row from the result.

F(n + 1) = f(n) – 8. if f(1) = 100, what is f(6)?

Sum of the interior angles of a pentagon