1.
\(2sin\left(-x\right)+4-6sin\left(-x\right)=0\)
\(\Leftrightarrow-2sinx+4+6sinx=0\)
\(\Leftrightarrow4sinx-4=0\)
\(\Leftrightarrow sinx=1\)
\(\Rightarrow x=\dfrac{\pi}{2}+k2\pi\)
2.
ĐKXĐ; \(x\ne\left\{\dfrac{\pi}{4}+\dfrac{k\pi}{2};k\pi\right\}\)
\(\left(tan2x+1\right)\left(2cotx-3\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}tan2x=-1\\cotx=\dfrac{3}{2}\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}2x=-\dfrac{\pi}{4}+k\pi\\x=arcot\left(\dfrac{3}{2}\right)+k\pi\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{\pi}{8}+\dfrac{k\pi}{2}\\x=arccot\left(\dfrac{3}{2}\right)+k\pi\end{matrix}\right.\)
