Question

Check whether the following matrices are invertible or not:

`[(1, 2, 3),(2, 4, 5),(2, 4, 6)]`

Answer 1

Let A = `[(1, 2, 3),(2, 4, 5),(2, 4, 6)]`

Then, |A| = `|(1, 2, 3),(2, 4, 5),(2, 4, 6)|`
= 1(24 – 20) – 2(12 – 10) + 3(8 – 8)
= 4 –  4 + 0
= 0
∴ A is a singular matrix.
∴ A is not invertible.