Question

Find the co-factor of the element of the following matrix:

`[(-1, 2),(-3, 4)]`

Answer 1

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

Here, a₁₁ = −1, M₁₁ = 4

∴ A₁₁ = (−1)¹⁺¹(4) = 4

a₁₂ = 2, M₁₂ = −3

∴ A₁₂ = (−1)¹⁺²(−3) = 3

a₂₁ = −3, M₂₁ = 2

∴ A₂₁ = (−1)²⁺¹(2) = −2

a₂₂ = 4, M₂₂ = −1

∴ A₂₂ = (−1)²⁺²(−1) = −1