#11: First term is 2. Formula for the (n+1)th term is (previous term) + 3.
Thus, we have 2, 5, 8, 11, 14, ... This is an arithmetic sequence with common difference 3.
#12 First term is -4. Formula for the (n+1)th term is (previous term) + n^2.
Second term (n=2): -4 + (2^2) = 0
Third term (n=3) : 0+3^2 = 9
Fourth term (n=4): 9 + 4^2 = 25
Fifth term (n=5) : 25 + 5^2 = 50
