Compute the cofactors $\displaystyle C_{12}, C_{22}, C_{32} $ for the matrix A =

[ 1 2 3 ]

[ 2 1 3 ]

[ 1 -1 1]. Use the cremar's rule to find x_2 when Ax = [1 -2 1]^T

I got the $\displaystyle C_{12} = -5, C_{22} = -4 , C_{32} = -3 $, how do I find $\displaystyle x_2$?