Question

Given that A^-1= `1/7 [(2,1),(-3,2)]`, matrix A is ______.

Options

• `7 [(2,-1),(3,2)]`

• `[(2,-1),(3,2)]`

• `1/7 [(2,-1),(3,2)]`

• `1/49 [(2,-1),(3,2)]`

Answer 1

Given that A^-1= `1/7 [(2,1),(-3,2)]`, matrix A is `underlinebb([(2,-1),(3,2)])`.

Explanation: 

We know that

(A^-1)^-1 = A

A^-1 `=[(2/7,1/7),(-3/7,2/7)]`

A = `(adj (A^-1))/|A^-1|`

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