Question 1112878
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Standard way to solve such problems is to introduce new variable


u = tan(x).


Then your equation takes the form


{{{4u^2 + 5u + 1}}} = 0.


You can factor left side 


(4u+1)*(u+1) = 0


and it gives you the solutions


u = {{{-1/4}}},  u = -1.


Thus  EITHER  tan(x) = {{{-1/4}}}  ====>  x = {{{arctan(-1/4)}}}   OR  tan(x) = -1   and  x = {{{arctan(-1)}}} = -45 degs.
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The advise by @Alan is right, without any doubt.


With only one notice: &nbsp;&nbsp;The person who is able to follow to this advise, &nbsp;will never come to this forum with such a question.


Since he &nbsp;(or she) &nbsp;will do everything on his &nbsp;(or her) &nbsp;own.


In other words, &nbsp;this advise does not work (is useless) for a person who came to &nbsp;<U>this forum</U> &nbsp;&nbsp;<U>with such a question</U>.


Although, again, &nbsp;the advise itself is absolutely correct.