Question

How do I use the subtraction theorem to write equivalent expressions?

Answer 1

The subtraction theorem states that for all real numbers, $a$ and $b$, $a-b=a+(-b)$.
(To subtract, we can add the inverse.)
Thus, we can have the these two equivalent expressions.

$3 - 2 = 3 + (-2) = 1\\ \\ 5 - (-2) = 5 + 2 = 7$