\[b_{1} = 7;\ \ b_{5} = 567\]
\[b_{5} = b_{1} \cdot q^{4}\]
\[567 = 7q^{4}\]
\[q^{4} = 567\ :7\]
\[q^{4} = 81\]
\[q = \pm 3\]
\[Ответ:q = 3.\]