Given :
A line 2x + 1 =0 .
To Find :
The slope of the given line .
Solution :
We know , slope of line is given by the tangent of the angle between the x-axis and the line .
Now, for line 2x + 1 =0 i.e [tex]x=\dfrac{-1}{2}[/tex] .
The line is perpendicular to x-axis and cuts the x-axis at [tex]\dfrac{-1}{2}[/tex] .
Therefore , the angle between the line and x-axis is [tex]90^o[/tex] .
So , slope [tex]m=\tan\ 90^o[/tex] i.e undefined .
Therefore , the slope of given line is not defined .
Hence , this is the required solution .