well you can try rewriting it to this
answer is d 270
first start of by factoring and subtracting the 1 into the right side
sin(x) ( 2 sin (x) + 1) = -1
set each one equal to -1
sin( x) = -1 and 2 sin (x) +1 = -1
2 sin (x) = -2
sin ( x) = -1
so therefore we have our final equation
sin ( x ) = - 1 and sin (x) = -1
so then you look in your unit circle and find what coordinate equals -1 in terms of sin x