\begin{frame}
  \frametitle{Linear Functions}
  
  \begin{block}{}
    A \emph{linear function} is a function $f$ that can be written in the form:
    \begin{align*}
      f(x) = mx + b
    \end{align*}
    where $m$ is the \emph{slope} and $b$ is the \emph{$y$-intercept}.
  \end{block}
  
  \pause\medskip
  The graph of a linear function is a line:
  \begin{center}
  \scalebox{.6}{
  \begin{tikzpicture}[default]
    \diagram{-2}{4}{-2}{4}{1}
    \diagramannotatez
    \diagramannotatex{-1,1,2,3}
    \diagramannotatey{-1,1,2,3}
    \draw[cblue,ultra thick] plot[smooth,domain=-1/3:2-1/3,samples=20] (\x,{3*\x - 1}) node[right] {$f(x) = 3x - 1$};
  \end{tikzpicture}
  }    
  \end{center}
\end{frame}