# Algebra

posted by
**Holly**
.

I am given a graph of a parabola and I have to write a function in at least two forms that will produce the graph. I think that I can write the factored form first since I have the two x-intercepts but I don't know what the "a" is in the equation y= a(x-r1)(x-r2). How do I find the "a" so I can write the equation?