Using elementary

First of all we need to check whether the matrix is invertible or not. For that-

For the inverse of a matrix A to exist,

Determinant of A ≠ 0

Here ∣A∣ = (2)(4) – (1)(7) = 1

So the matrix is invertible.

Now to find the inverse of the matrix,

We know AA^-1 = I

Let’s make augmented matrix-

→ [ A : I ]

→

Apply row operation- R₂→ R₂ – R₁

→

Apply row operation- R₂→ 2R₂

→

Apply row operation- R₁→ R₁ –R₂

→

Apply row operation- R₁→ R₁

→

The matrix so obtained is of the form –

→ [I : A^-1]

Hence inverse of the given matrix-

→