.
Standard way to solve such problems is to introduce new variable
u = tan(x).
Then your equation takes the form
= 0.
You can factor left side
(4u+1)*(u+1) = 0
and it gives you the solutions
u = , u = -1.
Thus EITHER tan(x) = ====> x = OR tan(x) = -1 and x = = -45 degs.
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The advise by @Alan is right, without any doubt.
With only one notice: The person who is able to follow to this advise, will never come to this forum with such a question.
Since he (or she) will do everything on his (or her) own.
In other words, this advise does not work (is useless) for a person who came to this forum with such a question.
Although, again, the advise itself is absolutely correct.