log 6 (3*b)=log 6 (5-(2*b))

log6(3*b)=log6(5-(2*b))

$\begin{array}{rcll} log_6(3b) &=& log_6(5-2b) \\ 3b &=& 5-2b\\ 5b &=& 5\\ b &=& 1 \end{array}$