Year 9 Interactive Maths - Second Edition

Quadratic Equations

The Null Factor Law

From this we can infer that:

If the product of any two numbers is zero, then one or both of the numbers is zero.

I.e.  If ab = 0, then a = 0 or b = 0 (which includes the possibility that a = b = 0)

This is called the Null Factor Law; and we use it often to solve quadratic equations. 

Example 1

Solution:

Key Terms

quadratic equation, Null Factor Law, NFL