In order to expand this logarithm, we can use the following property:
[tex]\log_a(b\cdot c)=\log_ab+\log_ac[/tex]
So, expanding the given logarithm, we have:
[tex]\begin{gathered} \log_b(7x\cdot2y)\\ \\ =\log_b7x+\log_b2y\\ \\ =\log_b7+\log_bx+\operatorname{\log}_b2+\operatorname{\log}_by \end{gathered}[/tex]
