[tex] \bf 7sin^2(x)-14sin(x)+2=-5\implies 7sin^2(x)-14sin(x)+7=0
\\\\\\
\stackrel{\textit{notice, this is just }ax^2+bx+c}{\stackrel{\stackrel{ax^2}{\downarrow }}{sin^2(x)}\stackrel{\stackrel{bx}{\downarrow }}{-2sin(x)}\stackrel{\stackrel{c}{\downarrow }}{+1}}=0\implies [sin(x)-1][sin(x)-1]=0
\\\\\\
sin(x)-1=0\implies sin(x)=1\implies \measuredangle x=sin^{-1}(1)\implies \measuredangle x=\cfrac{\pi }{2}
\\\\\\
~~~~~~~~~~~~~~\stackrel{\textit{and for all solutions using }n \in \mathbb{Z}}{\cfrac{\pi }{2}+2\pi n} [/tex]
