We have to write the equation of a line that is perpendicular to the line [tex]x=3[/tex] and that passes through the point [tex](0,-4)[/tex].
The general equation of a line in the slope-intercept form is given by:
[tex]y=mx+b[/tex]
Where, 'm' is the slope and 'b' is the y-intercept.
Now, we need to find the slope first,
The required line is perpendicular to the line [tex]x=3[/tex]. Slope of the line [tex]x=3[/tex] is undefined. A line perpendicular to that must have slope of '0'. That implies, our required line is parallel to the x-axis.
Therefore, m=0
Now that line is passing through the point [tex](0, -4)[/tex].
We can plug in the points to the find the value of y-intercept. After plugging the values, we get:
[tex]y=0 \times 0+(-4)=-4[/tex]
Hence, the equation of the required line is [tex]y=-4[/tex].