The DOS program basicgph allows you to practice determining the equation of the function from the graph of a given parabola.
Click on the above link to download.
Run the program as instructed under the DOS Applications link on the homepage (just double-click on the name of the downloaded program on the desktop on in Explorer).
When you run the program, you will want to choose 'Determine function from graph', choose a background color, and choose 'Generate Parabolas'.
Determine the equations of the given parabolas from their graphs: Click here for the graphs