Answer:
a(77) = 4 + 630 = 634
Step-by-step explanation:
This is an arithmetic sequence with first term 4 and common difference 9:
a(n) = a(1) + d(n - 1), or, specifically to this question, a(n) = 4 + 9(n - 1).
Then the 71st term is a(77) = 4 + 9(71 - 1), or a(77) = 4 + 630 = 634
