Find x, sin((2x+3))=cos((x-12))

Question

I am doing study island and am stuck on this problem. I have to find X.

Answer 1

when do sine & cosine have equal values?  when their arguments are equivalent to 45 degrees or 225 degrees.

 

therefore 2x+3 = x-12  which means x = -15.  But what does this mean? Is it in radians or degrees?  

 

Can you check the answers?    A rather unusual problem, it seems to me.