# Cubics

The most basic cubics questions might ask you to factorise a simple cubic where a factor of x can be taken out first.

**Example**: . Note that the discriminant of is which is negative and so has no roots. It follows that the original cubic cannot be factorised further.

Other cubics questions might involve factorising a more general cubic and may require knowledge of the factor theorem. See Example 2.

### Example 2

- Given that is a root of the cubic , factorise it completely.
- Factorise completely.