I've been trying to solve this recurrence relation
I used $Cr^n$ to factor which I got $r^2+r+1$, but I can't factor this, so I used the quadratic formula and I got $(-1+\sqrt{\mathstrut -3})/2$ and $(-1-\sqrt{\mathstrut -3})/2$.
Is this the right approach? I don't know what to do after this, I'd appreciate the help