Final answer:
The exponent property used to make the expression true is The power of a power property.
Step-by-step explanation:
The exponent property used to make the expression true is The power of a power property. This property states that when you raise an exponent to another exponent, you multiply the exponents. For example, if the expression is written as (a^x)^y, the power of a power property tells us that it can be simplified as a^(x*y). This property helps simplify and manipulate expressions involving exponents.