#### Answer

$m=\text{undefined}$

#### Work Step by Step

$\bf{\text{Solution Outline:}}$
To find the slope and the graph of the given equation, $
x-3=0
,$ use the slope and graph of lines in the form $x=a.$
$\bf{\text{Solution Details:}}$
In the form $x=a,$ the given equation is equivalent to
\begin{array}{l}\require{cancel}
x-3=0
\\\\
x=3
.\end{array}
Since lines of the form $x=a,$ have an undefined slope, then the slope of the line defined by the equation above is
\begin{array}{l}\require{cancel}
m=\text{undefined}
.\end{array}
The graph of lines in the form $x=a$ is a vertical line that passes through the $x$-axis at $a.$