The sixteenth and seventeenth terms of an arithmetic sequence are 8 and 10, respectively. What is the second term?

The common difference is 2.

The formula for the n^th term of an arithmetic sequence:  t_n  =  t₁ + (n - 1)d

The 16^th term is 8   --->   n = 16   --->   8  =  t₁ + (16 -1)(2)

                                                              8  =  t₁ + (15)(2)

                                                               8  =  t₁ + 30

--->   t₁  =  -22

--->   t₂  =  -22 + 2  =  -20