Answer:
Please specify what the three expressions are.
Explanation:
From what I understand, you need to set the expressions equal to each other. For instance, if one is 2(x-3) and the other is 2x-6, you could write it as:
Then, by evaluating it, you would get:
by distribution over subtraction.
by the additive property of equality
Simplify.
by the reflexive axiom.
Since x will always equal itself, 2(x-3) and 2x-6 are equivalent.
Therefore, if the expressions, once set equal to each other, result in the equation x=x, or any other expression in which one quantity equals itself, the two expressions are equal.
Sorry I could not be of more help, but you did not specify what the expressions were.