Question

If A is a square matrix of order 2, then det(-3A) is *

a. 3 det A
b. -3 det A
c. 9 det A
d. -9 det A
Help please.​

Answer 1

c. 9 det A

Explanation:

Given the following data;

Since A is a square matrix of order 2, we know that n = 2

K = 3

For any scalar k;

∣kA∣ = k^{n} ∣A∣

Substituting into the equation;

∣-3A∣ = -3²∣A∣

Simplifying, we have;

∣-3A∣ = 9∣A∣

= 9 detA

Therefore, det (-3A) = 9 detA