So, as we all know,
$$(a-b)(a+b) = a^2 - b^2$$
I remember learning a special piece of vocabulary in high school related to this.
$(a-b)$ is the _____ of $(a+b)$.
$(a+b)$ is the _____ of $(a-b)$.
For any binomial, you can form its ______ by reversing the sign of its second term.
Can you guys help me fill in the blank?