find the equation of the parabola(the picture)

You may wish to post some of your thoughts so we know where you're hung up.

You may wish to post some of your thoughts so we know where you're hung up.
I don't know how to solve this problem.. I need a step-by-step process

There's not enough info. What's the x value of the vertex? 1, perhaps. All I see is a y value.

Let's say it is 1. The vertex has coordinates (1,-2) and the parabola passes through (2,0).

You can use y=a(x-h)^{2}+k

(h,k) is the coordinates of the vertex and (x,y) is the point it passes through. Enter your values and solve for 'a'.