How to solve for $a$
$a\pm k$(k being any real number other $0$)=$\frac{a}{a}=a^2=a$ Find $a$ ( $k$ is any real number other than $0$
The only solution I could think of is $$\frac{0}{0}$$
But does it belong to real numbers and is my solution correct?
$$a \pm k = \ldots = a \implies a \pm k - a = 0 \implies \pm k = 0$$