The subtraction theorem states that for all real numbers, [tex]a[/tex] and [tex]b[/tex], [tex]a-b=a+(-b)[/tex].
(To subtract, we can add the inverse.)
Thus, we can have the these two equivalent expressions.
[tex]3 - 2 = 3 + (-2) = 1\\ \\ 5 - (-2) = 5 + 2 = 7[/tex]
