Question 413791
It should be a simple equation, since it's solvable in two or so steps.


Divide both sides by 3, then take the square root:


{{{x^2 = 7/3}}}


{{{x = 0 +- sqrt(7/3) = 0 +- sqrt(7)/sqrt(3)}}} (ignore the 0, the site won't let me parse +- without something in front...)


To rationalize the denominator, multiply both top and bottom by {{{sqrt(3)}}}. Hence,


{{{x = (0 +- sqrt(7)/sqrt(3))(sqrt(3)/sqrt(3)) = 0 +- sqrt(21)/3}}}.