Roots of polynomials

What you'll learn

1. 1

   Imagine a polynomial like a big number machine. Its roots are the numbers you feed in that make the machine output zero.

2. 2

   Let's find the root of x² - 5x + 6 = 0 together.

3. 3

   What is a root of the polynomial x² - 4?

4. 4

   Here's a graph of x² - 5x + 6. The roots are where the curve crosses the x-axis — at x = 2 and x = 3.

5. 5

   Drag the points to match the roots of x² - 4 = 0 on this number line.

6. 6

   If a polynomial has a root at x = -1, what happens when you put -1 into the polynomial?

7. 7

   What about a cubic? Find the roots of x³ - 6x² + 11x - 6 = 0.