Answer:
Step-by-step explanation:
Case 1: 20; Case 2: 36
Case 1: arithmetic sequence
The common difference is 8. Notice that 4 + 8 = 12.
a(1) = 4; a(2) = 12; a(3) = 20; etc.
The common next term (3rd term) is 20.
Case 2: geometric sequence
The common ratio is 3. Notice that 4*3 = 12.
Multiplying this second term by the common ratio (3) results in the third term: 36.