Answer
$$x=\frac{\pi }{3}+\pi n,\:x=\frac{2\pi }{3}+\pi n$$
Work Step by Step
We solve the equation using the properties of trigonometric functions. Note, there is a general solution since trigonometric identities go up and down and this can pass through a given value of y many times. Solving this, we find:
$$3\tan ^2\left(x\right)-9=0 \\ tan(x)=\pm \sqrt3 \\ x=\frac{\pi }{3}+\pi n,\:x=\frac{2\pi }{3}+\pi n$$
