Question

What are the solution(s) of x^2-4=20?

Answer 1

$x^2-4=20\qquad|+4\\\\x^2=24\to x=\pm\sqrt{24}\\\\x=-\sqrt{4\cdot6}\ \vee\ x=\sqrt{4\cdot6}\\\\x=-2\sqrt6\ \vee\ x=2\sqrt6$