Multiple examples graphing parabolas using roots and vertices : Khan Academy on a Stick

Khan Academy on a Stick

Graphing quadratics

Graphing a parabola with a table of values
Parabola vertex and axis of symmetry
Graphing a parabola by finding the roots and vertex
Finding the vertex of a parabola example
Multiple examples graphing parabolas using roots and vertices
Graphing a parabola using roots and vertex
Shifting and scaling parabolas
Parabola intuition example 1
Graphing a parabola in vertex form

If the above player doesn't work, try this direct link.