This is LaTeX code:

[latex]
 
 (-1)^{1+1}\cdot 1\cdot det(\left(\begin{array}{cc}
4 & 5\\ 5 & 6
\end{array}\right))+(-1)^{2+1}\cdot 0\cdot det(\left(\begin{array}{cc}
2 & 3\\ 5 & 6
\end{array}\right))+(-1)^{3+1}\cdot 0\cdot det(\left(\begin{array}{cc}
2 & 3\\ 4 & 5
\end{array}\right))
 
[/latex]