Let's plot the line with equation \(y=3\text{.}\) (Note that this is the same as \(0x+1y=3\text{.}\))

To plot some points, it doesn't matter what \(x\)-values we use. All that matters is that \(y\) is always \(3\text{.}\)

A line like this is horizontal, parallel to the horizontal axis. All lines with an equation in the form

\begin{equation*} y=k \end{equation*}

(or, in standard form, \(0x+By=C\)) are horizontal.

a horizontal line at y=3