Answer
See the image below.
Work Step by Step
For a rough sketching, we can simply draw the similar figure we have on the upper half of $x$-axis to the lower half. (See the image above)
For a more precise sketching, we can take negative values of $y$ and find several points on the lower side of $x$-axis. Plot these points and connect them according to the form we have on the right hand side.