行列式/二階行列式/計算練習

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