Question

Write the value of the determinant |3-1 2-1|

Answer 1

$\textsf{Determinant:}$

$\textsf{To every square matrix A, we can associate}$

$\textsf{ a real number called determinant of A }$

$\textsf{It is denoted by }|A|$

$\textsf{The second order determnant is calculated as follows:}$

$\left|\begin{array}{cc}a&b&\\c&d\end{array}\right|=ad-bc$

$\text{Now,}$

$\left|\begin{array}{cc}3&-1\\2&-1\end{array}\right|=3(-1)-2(-1)$

$\left|\begin{array}{cc}3&-1\\2&-1\end{array}\right|=-3+2$

$\implies\bf\left|\begin{array}{cc}3&-1\\2&-1\end{array}\right|=-1$