**The Principle of Zero Products**

The product of two numbers is 0 is one or both of the numbers is 0. Further-more, if any product is 0, then a factor must be 0. For example:

If 7x = 0, then we know that x = 0.

If x(2x – 9) = 0, then we know that x = 0 or 2x – 9 = 0.