This equation is the vertex form of a parabola y = a(xh)^{2} + k. In this case, a is 1, which means no stretching or shrinking. A positive k value translates up and a negative k value translates down. A positive h value shifts the graph right and a negative h value shifts the graph left. Hint: Notice the term xh and what would happen if h was negative.
6/7/2014

Alex S.