Let $M$ be a $3 \times 3$ invertible matrix with real entries and let $I$ denote the $3 \times 3$ identity matrix. If $M ^{-1}=\operatorname{adj}(\operatorname{adj} M )$, then which of the following statement is/are $ALWAYS TRUE$ ?

$(A)$ $M=I$   $(B)$ $\operatorname{det} M =1$   $(C)$ $M ^2= I$  $(D)$ $(\operatorname{adj} M)^2=I$

$\left| {\,\begin{array}{*{20}{c}}{a – b – c}&{2a}&{2a}\\{2b}&{b – c – a}&{2b}\\{2c}&{2c}&{c – a – b}\end{array}\,} \right| = $

The value of $\left| {\,\begin{array}{*{20}{c}}{441}&{442}&{443}\\{445}&{446}&{447}\\{449}&{450}&{451}\end{array}\,} \right|$ is

Verify Property $2$ for $\Delta=\left|\begin{array}{ccc}2 & -3 & 5 \\ 6 & 0 & 4 \\ 1 & 5 & -7\end{array}\right|$

If $A$, $B$ and $C$ are the angles of a triangle then the value of the determinant

$\left| {\begin{array}{*{20}{c}}
  { – 1 + \cos B}&{\cos C + \cos B}&{\cos B} \\ 
  {\cos C + \cos A}&{ – 1 + \cos A}&{\cos A} \\ 
  { – 1 + \cos B}&{ – 1 + \cos A}&{ – 1} 
\end{array}} \right|$