If A is a 3 × 3 matrix, |A| ≠ 0 and |3A| = k|A| then write value of k.
We are given that,
Order of matrix = 3
|A| ≠ 0
|3A| = k|A|
We need to find the value of k.
In order to find k, we need to solve |3A|.
Using property of determinants,
|kA| = kn|A|
Where, order of A is n × n.
Similarly,
|3A| = 33|A|
[∵, order of A is 3]
⇒ |3A| = 27|A| …(i)
As, according to the question
|3A| = k|A|
Using (i),
⇒ 27|A| = k|A|
Comparing the left hand side and right hand side, we get
k = 27
Thus, the value of k is 27.