Identify the explicit function for the sequence in the table x y 1 7 2 19 3 31 4 43 5 55 choices: a. a(n)=7(n-1) b. a(n)=7+(n-1)•12 c. a(n)=12+(n-1)•7 d. a(n)=12(n-1)

The common difference is 19-7 = 31-19 = 12, so this is an arithmetic sequence. The initial term (when n=1) is 7.

The explicit formula for the terms of an arithmetic sequence is
  an = a1 + d(n-1)
where "a1" is the first term and "d" is the common difference. The formula that matches a1=7 and d=12 is
  B. a(n) = 7+(n-1)·12