Answer:
- one negative real root in [-5, -4]; two complex roots
- the complex roots cannot be isolated in the same way.
Step-by-step explanation:
A graphing calculator is a wonderful tool for this. It shows the one real root to be near -4.062, so between -5 and -4.
The value of the cubic at x = -5 is -315; at -4 it is +15, so the root is definitely between those values.
The one real root is isolated to being between (-5, -315) and (-4, 15). The complex roots are not isolated.
