Question

X square +2 under root 2 X minus 6 =0

Answer 1

$x^2 + 2\sqrt{2x} - 6$

=> $x^2 + 3\sqrt{2}x - \sqrt{2}x - 6$

=> $x(x + 3\sqrt{2}) - \sqrt{2}(x + 3\sqrt{2})$

=> $\color{red}\fbox{(x - \sqrt{2}) (x + 3\sqrt{2})}$