142. Find the coordinates of the focus and the equation of the directrix of the parabola given by the equation $y^{2}=8 x$.
Solution. From the given canonical equation of the parabola, it follows that $2 p=8$, i.e., $p=4$, from which $p / 2=2$. Therefore, the point $F(2 ; 0)$ is the focus of the parabola, and $x=2$ is the equation of its directrix.