Linear algebra adjoint, determinant

[Mdhiggenz]

Homework Statement

Given A=[1 2 1; 0 4 3; 1 2 2]
determine the (2,3) entry of A^-1 by computing a quotient of two determinants.

This problem confused me a bit, do they just want us to divide the adj(A) by the det(A) in order which would give us A^-1 and just state the (2,3) entry from there?

Thanks

Higgenz

Homework Equations

The Attempt at a Solution

 

[Dick]

Homework Statement

Given A=[1 2 1; 0 4 3; 1 2 2]
determine the (2,3) entry of A^-1 by computing a quotient of two determinants.

This problem confused me a bit, do they just want us to divide the adj(A) by the det(A) in order which would give us A^-1 and just state the (2,3) entry from there?

Thanks

Higgenz

Homework Equations

The Attempt at a Solution

You don't need to compute the whole A^(-1). But as you say, they just want you to compute adj(A)(2,3)/det(A). Just the one entry of A^(-1).