Hello, shawsend!
I don't know what they mean by "a single plot."
Since the roots are complex, how are we to graph them?
Draw a single plot showing the parabola $\displaystyle f(x)=x^24x+5$
and where the roots are in relation to it.
The roots are: .$\displaystyle x \:=\:2 \pm i$
Where are they? . . . Well, they are not on the $\displaystyle xy$plane
If we had an $\displaystyle i$axis coming out of the $\displaystyle xy$plane,
. . the graph might look like this:
Code:
y
 *

* *
* *
 * *
 *
 :
+   *     x
/ /
/ *
/ (2,0,1)
i/
One root is on the "floor" at (2,0,1).
The other is (2,0,1), one unit "behind" the $\displaystyle xy$plane.