Know : \left\{ \begin{array}{l}<br /> \log _a \left( b \right) = \frac{2}{3} \\ <br /> lug_c \left( d \right) = \frac{4}{5} \\ <br /> a - c = 9 \\ <br /> \end{array} \right.<br />
calculate : b - d
a,b,c,d naturels numbers.