Question

Determine the values of a and b so that the following matrices are singular:

A = `[(7, 3),(-2, "a")]`

Answer 1

A = `[(7, 3),(-2, "a")]`

|A| = `[(7, 3),(-2, "a")]`

|A| = 7a + 6

Given that A is singular

∴ |A| = 0

7a + 6 = 0

⇒ a = `(-6)/7`