Hi Bryony.
y = x^{2}  2x  3 is a parabola. Since the x^{2} is positive, it opens upward (concaveup). If you factor the right hand side, you get (x+1) (x3) so that means that the
xintercepts are at 1 and +3. The vertex is halfway between these of course
(at x = 1). That means the vertex is at x = 1 and y = 1^{2}  2(1)  3 = 4.
So draw a parabola shape with the vertex at (1, 4) and x intercepts at 1 and +3.
Hope this helps,
Stephen La Rocque.
