For some real number , the first three terms of an arithmetic sequence are and . What is the numerical value of the fourth term?
Select an Answer
The correct answer is E.
To determine the numerical value of the fourth term, first determine the value of and then apply the common difference.
Since , and are the first three terms of an arithmetic sequence, it must be true that , that is, Solving for gives . Substituting for in the expressions of the three first terms of the sequence, one sees that they are , , and , respectively. The common difference between consecutive terms for this arithmetic sequence is , and therefore, the fourth term is .