[tex]4log_{216}6\\\\use:\ log_ab=\frac{log_cb}{log_ca}\\\\4log_{216}6=4\cdot\frac{log_66}{log_6216}=4\cdot\frac{1}{log_66^3}=\boxed{\frac{4}{3}}[/tex]
[tex]2log_\frac{1}{2}\frac{1}{16}=2log_\frac{1}{2}\left(\frac{1}{2}\right)^4=4\cdot2log_\frac{1}{2}\frac{1}{2}=4\cdot2\cdot1=\boxed8[/tex]
