Before you tackle this problem see
Root Tracker.
In this problem you must first observe the path of the roots of the
quadratic equations x2 + px + q = 0 as you change p and keep
q fixed.
You can change the equation x2 + px +q = 0 by moving the point
(p, q) in the red frame. You can see how the graph of y=x2 + px + q
changes in the blue frame. The Argand Diagram in the green frame shows the
roots of the quadratic equation. Look for two roots in the Argand diagram
and watch them move as
you change the driving point (p,q) in the red frame, and in doing so
change the quadratic equation and its roots.
What do you notice
about the paths that these roots follow when you change p and keep
q fixed? Make a conjecture about the curves on which the complex roots lie.