Question

if |2A| = 40 find |adj A|, where A is a matrix of order 3x3

a 1600
b 20
c 2√10
d √10
e none of these ​

Answer 1

Answer:

e none of these

Reason:-

As the solution of this question is 25, which does not appear in any of the given options, we should ho ahead with option e i.e. none of these.

Answer 2

Step-by-step explanation:

Consider the following identity A(adjA)=∣A∣I. Thus comparing it with the above equation gives us ∣A∣=10

Now ∣adjA∣=∣A∣n−1 where n is the order of the square matrix.

Here 'n' is 3, therefore, ∣adjA∣=∣A∣3−1=∣A∣2=102=100.