Find Stretch to Match a Point

What value of "a" will make the graph pass through the point (-3,4)

This quadratic is y = a(x + 4)(x - 2). How can you obtain the (x + 4) and (x - 2) from the graph?

Play with the vertical stretch and observe the x intercepts. Does changing the stretch "a" change the x intercepts?

What is the axis of symmetry?