an arithmetic sequence....we need a common number to add to each term to find the next term. The number is called the common difference and can be found by subtracting the first term from the second term. So the common difference is (4 - 2) = 2. What this means is when u add 2 to each erm, u get the next term.
an = a1 + (n - 1) * d n = term to find = 7 a1 = 1st term = 2 d = common difference = 2 now we sub and solve a7 = 2 + (7 - 1) * 2 a7 = 2 + 6 * 2 a7 = 2 + 12 a7 = 14 <===== this is a7
