If$ (x-a)^2=(x+a)^2$ for all values of $x$, then what is the value of a?

Question

If $(x-a)^2=(x+a)^2$ for all values of $x$, then what is the value of $a$? Please help, thanks.

Answer 1

Hint: Expand the quadratic terms and eliminate like terms.

Answer 2

Hint: What happens if you choose $x=a$?