9 and -1944 The sequence is a1, a2, a3, a4 where the two middle terms are the two geometric means. Using the formula for the nth term a1, a1r, a1r², a1r³ a1 = 9, So the sequence is 9, 9r, 9r², 9r³ a4 = 9r³ = -1944 r³ = -216 r = -6 The two means are 9r and 9r², which are 9(-6) = -54 and 9(-6)² = 9(36) = 324 Edwin