# What is the slope of the line x=-2?

The slope is mathematically 'undefined'. It is a line parallel to the y axis passing through $x = - 2$
By definition the slope (gradient) is $\left(\text{change in y axis")/("change in x axis}\right)$
There is no change in the x axis. so we have $\frac{\text{change in y axis}}{0}$ which is undefined