Respuesta :

[tex]7 \sin^2 x - 14 \sin x +7 = 0\\\\\implies 7 \sin^2 x - 7 \sin x - 7 \sin x +7 =0\\\\\implies 7 \sin x(\sin x -1) - 7( \sin x -1) =0\\\\\implies (\sin x -1)(7 \sin x -7) =0\\\\\implies \sin x = 1\\\\\implies x =\dfrac{\pi}2 + 2 \pi n\\[/tex]