Investigating Quadratic Graphs in Vertex Form

This worksheet allows you to investigate quadratic graphs given in Vertex Form. Use the sliders to change the values of a, b and c and note what happens to the shape of the graph, and the position of the vertex. How can you work out the y-intercept from the equation?
For a quadratic graph given in the form y=a(x+b)^2 +c 1. How can you tell where the vertex of the graph will be? 2. How can you work out where the graph will cut the y-axis?