Formulaic Properties
Define a * b = 2a + b. Find values of x, y, and z, so that (x * y) * z = 18

Extensions 
Provide an example using values x, y, and z, that would illustrate the associative property. Give another example that would illustrate the commutative property.
(Source: Adapted from Mathematics Teaching in the Middle School, Jan 1997) 
Submit your idea for an investigation to InterMath.
