Hello, flakine!
Use the same technique for the first one . . .
We have: .\(\displaystyle \tan x\,+\,\sec x\:=\:\sqrt{3}\)
Then: .\(\displaystyle \sec x\:=\:\sqrt{3}\,-\,\tan x\)
Square: .\(\displaystyle \sec^2x\:=\:3\,-\,2\sqrt{3}\cdot\tan x\,+\,\tan^2x\)
. . \(\displaystyle \tan^2x\,+\,1\:=\:3\,-\,2\sqrt{3}\cdot\tan x\,+\,\tan^2x\)
which simplifies to: .\(\displaystyle 2\sqrt{3}\cdot\tan x\:=\:2\;\;\Rightarrow\;\;\tan x\,=\,\frac{1}{\sqrt{3}}\;\;\Rightarrow\;\;x\,=\,\frac{\pi}{6},\,\frac{7\pi}{6}\)
And, as tkhunny cautioned, check these answers.