a)[tex] log_{2}x= log_{2} \frac{64}{16} \\ log_{2} x= log_{2}4 \\ x=4 \\ b) log_{ \sqrt{7} }x= log_{ \sqrt{7} }16 - log_{ \sqrt{7} }2+ log_{ \sqrt{7} }5 \\ [/tex]
[tex] log_{ \sqrt{7} }x= log_{ \sqrt{7} } \frac{16}{2}*5 \\ x=40 \\ c) log_{4} x+ log_{16}x+ log_{2}x=7 [/tex]
[tex] log_{2}x+ log_{2} \sqrt{x} + log_{2} \sqrt[4]{x}=7 \\ x* \sqrt{x} * \sqrt[4]{x}=128 \\ x^{ \frac{7}{4} }=128 [/tex]
[tex] x^{ \frac{1}{4} }= 2 \\ x=16 [/tex]
