$$\left. \begin{array} { l } { \log _ { b } a + \log _ { c } a } \\ { \log _ { b } a \cdot \log _ { c } a } \end{array} \right.$$
$\log_{b}\left(a\right)+\log_{c}\left(a\right),\ \frac{\ln(a)^{2}}{\ln(b)\ln(c)}$
