y^2=-10x Graph the equation. Identify the focus, directrix, and axis of symmetry of the parabola.

Let y^2=4px  be equation of parabola. Then equation of directrix is x=-p coordinates of focus are (p,0) and axis of symmetry is x-axis.
In this case equation of parabola is
y^2=-10x
Therefore,
4p=-10
Divide by 4 in order to obtain p.
p=-10/4=-5/2
Using the facts stated at the beginning we can write the equation of directrix and coordinates of focus.
Directrix is the line x=5/2, focus is the point (-5/2,0) and axis of symmetry is x-axis.                        
https://en.wikipedia.org/wiki/Parabola