Question

B5=61 b11=1647 b2=? b9=?

Answer 1

$b_5=b_2\cdot q^3\Rightarrow b_2=\frac{b_5}{q^3}\\b_{11}=b_9\cdot q^2\Rightarrow b_9=\frac{b_{11}}{q^2}\\b_{11}=b_5\cdot q^6\\1647=61\cdot q^6\\q^6=27\\q=\sqrt[6]{27}=\sqrt3\\q^2=3,\;q^3=3\sqrt3\\b_2=\frac{61}{3\sqrt3}\\b_9=\frac{1647}{3}=549$