If sin theta +2 cos theta =1. p.t 2 sin theta - cos theta =2?

www.wolframalpha.com/input/?i=solve+sinx+%2B+2cosx+%3D+1
www.wolframalpha.com/input/?i=solve+2sinx+-+cosx+%3D+2

I have no idea how the computer did that. If you send them some money they will tell you.