\begin{frame}
  \frametitle{One-To-One Functions: Examples}
  
  \begin{exampleblock}{}
    Which of the following functions is one-to-one?
    \begin{itemize}
    \pause\medskip
      \item $x^3$\quad?\quad \pause Yes 
    \pause\medskip
      \item $x^2$\quad?\quad \pause No
    \pause\medskip
      \item $4^x$\quad?\quad \pause Yes
    \pause\medskip
      \item $x - x^3$\quad?\quad \pause No
    \pause\medskip
      \item $x + 4^x$\quad?\quad \pause Yes
    \pause\medskip
      \item $-x - x^3$\quad?\quad \pause Yes
    \medskip
    \end{itemize}
  \end{exampleblock}
\end{frame}