Question

A be a square matrix of order 4 × 4 , then what is the value of  |3A| . 
1. 27 |A|
2. 9 |A|
3. 3 |A|
4. 81 |A|

Answer 1

Correct Answer - Option 4 : 81 |A|

Concept: 

If A be a square matrix of order n × n , then |kA| = kⁿ |A| . 

Calculation: 

Given matrix A is the square matrix of order 4 × 4 , we know that |kA| = kⁿ |A| , where n be the order of matrix 

We have n = 4 

⇒ |3A| = 3⁴ |A| 

⇒ |3A| = 81 |A|  . 

The correct option is 4.