Polynomial functions
Weeks 1-2You can factor higher-degree polynomials, find all their zeros, and predict how the ends of the graph behave. You can also divide one polynomial by another.
- Use synthetic division to test whether x = 2 is a root.
- Factor x cubed - 8 as a difference of two cubes.
- Predict that an odd-degree polynomial with a positive lead falls on the left and rises on the right.
Worked example
Is x = 2 a root of x cubed - 3x squared + 4?
- Substitute: 8 - 3(4) + 4
- 8 - 12 + 4
Answer0, so yes, x = 2 is a root
Most common mistakeMultiplying before squaring: reading 3x squared at x = 2 as (3 x 2) squared = 36, so the total looks like -24 and the root is missed.