Here we go ~
[tex]\qquad \rm\dashrightarrow \: log_{b}(x) + log_{b}(y) [/tex]
we need to simplify this expression to one term with log having base "b", and it can be done by a logarithmic property, according to which the logarithmic expressions with same base being added can be depicted as multiplication of the terms inside log under same log with same base as the two.
And by doing so it can be depicted as :
[tex]\qquad \rm\dashrightarrow \: log_{b}((x) \times (y)) [/tex]
[tex]\qquad \rm\dashrightarrow \: log_{b}(xy) [/tex]
