Hi all again!

Hoping you can help me with this one as I dont really have a clue how to go about it properly:

$\displaystyle 2sin^2 x + 3cos x-3=0$

Ive used all kinds of identities and get really long and nonsensical answers, if someone could take me through step by step that would be ideal;

I have the answer, I just need to know how to arrive at it!

Thanks in advance!

Rhys.