Given the equation
[tex]3 tan(3x)=3[/tex] ⇒ divide both sides by 3
[tex]tan(3x)= \frac{3}{3} [/tex]
[tex]tan(3x)=1[/tex] ⇒ then take arctan of 1
[tex]3x= tan^{-1}(1) [/tex]
[tex]3x=45[/tex]°
From here we can read the solution on tan(x) graph between a certain interval.
Say the interval is 0°<x<360°, the graph of tan(x) is given below, there are two solutions between this interval
3x = 45° and 225° ⇒ dividing each answer by 3
x = 15°, 75° ⇒ these are the answer to the equation for the equation between 0° and 360°
