Answer :
In order to find the correct answers, let's simplify the equation by calculating the square root of both sides of the equation:
[tex]\begin{gathered} x^2=63\\ \\ x=\pm\sqrt{63}\\ \\ x=\pm\sqrt{3^2\cdot7}\\ \\ x=\pm3\sqrt{7} \end{gathered}[/tex]Therefore the correct options are 3√7 and -3√7.