A geometric sequence is defined by the equation an = (3)3 − n. What are the first three terms of the sequence and what is the common ratio, r? (1 point) 9, 3, 1; r = start fraction one over three end fraction 9, 3, 1; r = −6 9, 3, 0; r = start fraction negative one over three end fraction 9, 3, 0; r = 3