For Negative Pi Less Than or Equal to Theta which is less than or equal to Pi

find all solutions

2(sin^2 x - cos^2 x ) = 8sinx-5

x is theta, and it is not in the exponent.

I have issues solving trigonometric equations of this style because I seem to be unsure how to handle the exponents.

I seek assistance here as usual because the lack of my educator's teaching skills.