Answer
$${\text{the sequence is not geometric }}$$
Work Step by Step
$$\eqalign{
& {a_1} = - 7,{a_2} = - 5,{a_3} = - 3,{a_4} = - 1,{a_5} = 1,{a_6} = 3,... \cr
& {\text{to verify that the sequence is geometric}}{\text{, divide each term except the first by }} \cr
& {\text{the preceding term}} \cr
& \frac{{{a_6}}}{{{a_5}}} = \frac{3}{1} = 3 \cr
& \frac{{{a_5}}}{{{a_4}}} = \frac{1}{{ - 1}} = - 1 \cr
& {\text{the ratio is not constant}}{\text{, so}} \cr
& {\text{the sequence is not geometric }} \cr} $$
