1/4 and 64 can be expressed as follows:
[tex]\begin{gathered} \frac{1}{4}=4^{-1} \\ 64=4^3 \end{gathered}[/tex]Substituting into the equation:
[tex]\begin{gathered} (4^{-1})^{y+1}=4^3 \\ 4^{(-1)(y+1)}=4^3 \\ 4^{-y-1}=4^3 \\ -y-1=3 \end{gathered}[/tex]