Theres also a bunch of ways to solve these equations. The graph is a parabola. The graphs of quadratic equations are parabolas.
Watch this tutorial and get introduced to quadratic equations.
The variables h and k are the coordinates of the parabolas vertex. Parabolas have two equation forms standard and vertex. The variables h and k are the coordinates of the parabolas vertex. The following vertex formula will give us the x coordinate for the vertex of the parabola.