行列式/二階行列式/計算練習

1. $\left|\begin{array}{cc}2& 1\\ 5& 4\end{array}\right|=5$
2. $\left|\begin{array}{cc}0.5& 3\\ 1& 4\end{array}\right|=$
3. $\left|\begin{array}{cc}20& 3\\ 15& 4\end{array}\right|=$
4. $\left|\begin{array}{cc}\frac{1}{2}& 3\\ 1& 4\end{array}\right|=$
5. $\left|\begin{array}{cc}\frac{1}{2}& 3\\ -1& 4\end{array}\right|=$
6. $\left|\begin{array}{cc}-2& 3\\ 1& 4\end{array}\right|=$
7. $\left|\begin{array}{cc}2& \sqrt{3}\\ \sqrt{3}& 4\end{array}\right|=$
8. $\left|\begin{array}{cc}\sqrt{2}& -3\\ 1& \sqrt{18}\end{array}\right|=$
9. $\left|\begin{array}{cc}0& 0\\ 1& 4\end{array}\right|=$
10. $\left|\begin{array}{cc}{2}^3& 3^2\\ 1& 3\end{array}\right|=$