If the matrices A = \[\left[ {11113−1243 } \right]\],
B = adjA and
C = 3A, then \[{{\left| {adjB} \right|} \over {\left| C \right|}}\] is equal to :
Solutions · 1
Official solution
A = \[\left[ {11113−1243 } \right]\]
\[ \Rightarrow \] |A| = 6
\[{{\left| {adjB} \right|} \over {\left| C \right|}}\]
= \[{{\left| {adj\left( {adjA} \right)} \right|} \over {\left| {3A} \right|}}\]
= \[{{{{\left| A \right|}^4}} \over {{3^3}\left| A \right|}}\]
= \[{{{{\left| A \right|}^3}} \over {{3^3}}}\]
= \[{{{6^3}} \over {{3^3}}}\] = 8