12(4−3−21)\frac{1}{2}\left(\begin{array}{cc}4 & -3 \\-2 & 1\end{array}\right)21(4−2−31)
12(4−2−31)\frac{1}{2}\left(\begin{array}{cc}4 & -2 \\-3 & 1\end{array}\right)21(4−3−21)
−12(4−3−21)-\frac{1}{2}\left(\begin{array}{cc}4 & -3 \\-2 & 1\end{array}\right)−21(4−2−31)
−12(4−2−31)-\frac{1}{2}\left(\begin{array}{cc}4 & -2 \\-3 & 1\end{array}\right)−21(4−3−21)