The "2nd difference" consists of an arithmetic sequence of 4, 6, 8, .... , so it can be expressed by
a quadratic function.
that would be term(n) = n^2 + n + 6
term(7) = 49 + 7 + 6 = 62
if you don't know how to find that function you could just continue the pattern:
term1 = 8
term2 = term1 + 4 = 12
term3 = term2 + 6 = 18
term4 = term3 + 8 = 26
term5 = term4 + 10 = 36
term6 = term5 + 12 = 48
term7 = term6 + 14 = 62 <----- same as value obtained from formula of function
Seats in a theater are set up as the following:
The first row has 8 seats, the seconds row has 12 seats, the third row has 18 seats, and the fourth row has 26 seats. How many seats are in the 7th row?
1 answer