Question

Factorise:
$x^2-2\sqrt{2}x-30$

Answer 1

$$\begin{gathered} x^2-2\sqrt{2}x-30 \\ =x^2-5\sqrt{2}x+3\sqrt{2}x-30 \\ =x\left(x-5\sqrt{2}\right)+3\sqrt{2}\left(x-5\sqrt{2}\right) \\ =\left(x-5\sqrt{2}\right)\left(x+3\sqrt{2}\right) \end{gathered}$$