Can someone please let me know if i done this correctly?

And if there is a faster way I'd love to know.

$\displaystyle 3x = \sqrt{3+x}$

$\displaystyle 3x^2 = (3+x)^2$

$\displaystyle 3x^2 = 3^2 + x^2 $

$\displaystyle 3x^2 - x^2 = 3^2$

$\displaystyle 2x^2 = 3^2$

$\displaystyle \frac{2x^2}{2} = \frac{9}{2}$

$\displaystyle x^2 = 4.5 $

$\displaystyle x = 2.121$