College

Given that [tex]$L_1$[/tex] is parallel to the [tex]$x$[/tex]-axis, write down the equation of [tex]$L_1$[/tex].

(Note: [tex]$L_1$[/tex] is parallel to the [tex]$x$[/tex]-axis and passes through the point [tex]$A$[/tex] at [tex]$(0,4)$[/tex].)