\[b_{6} - b_{4} = 144:\]
\[b_{1}q^{5} - b_{1}q^{3} = b_{1}q^{3}\left( q^{2} - 1 \right) =\]
\[= q \cdot b_{1}q^{2}\left( q^{2} - 1 \right) = 144.\]
\[b_{5} - b_{3} = 48:\]
\[b_{1}q^{4} - b_{1}q^{2} = b_{1}q^{2}\left( q^{2} - 1 \right) = 48.\]
\[q \cdot 48 = 144\]
\[q = \frac{144}{48} = 3.\]
\[b_{1} \cdot (3)^{2} \cdot \left( 3^{2} - 1 \right) = 48\]
\[9b_{1} \cdot 8 = 48\]
\[9b_{1} = 6\]
\[b_{1} = \frac{6}{9}\]
\[b_{1} = \frac{2}{3}.\]
\[Ответ:\ \frac{2}{3};\ \ 3.\]