Реши уравнения

а) \(\left(\dfrac{1}{4}\right)^x=64\) ; \(x=\) [ ];

б) \(5^{3x-4}=25\) ; \(x=\) [ ];

в) \(\log\_6 x=-2\) ; \(x=\) [ ];

г) \(\log\_\frac{1}{4} (2x+1)=-1\) ; \(x=\) [ ].