Câu 16: Ý D
Pt\(\Leftrightarrow2sin\left(x+\dfrac{\pi}{6}\right)=0\)
\(\Leftrightarrow x+\dfrac{\pi}{6}=k\pi\)(\(k\in Z\)) \(\Leftrightarrow x=-\dfrac{\pi}{6}+k\pi\) (\(k\in Z\))
Tại \(k=0\Rightarrow x=-\dfrac{\pi}{6}\)
Tại \(k=-1\Rightarrow x=-\dfrac{7\pi}{6}\)