Find the inverse of matrix A=(120013101)A = \begin{pmatrix} 1 & 2 & 0 \\ 0 & 1 & 3 \\ 1 & 0 & 1 \end{pmatrix}A=101210031 using the adjugate formula.
A−1=15(1−263−1−3−121)A^{-1} = \frac{1}{5}\begin{pmatrix} 1 & -2 & 6 \\ 3 & -1 & -3 \\ -1 & 2 & 1 \end{pmatrix}A−1=5113−1−2−126−31
A−1=14(1−263−1−3−121)A^{-1} = \frac{1}{4}\begin{pmatrix} 1 & -2 & 6 \\ 3 & -1 & -3 \\ -1 & 2 & 1 \end{pmatrix}A−1=4113−1−2−126−31
A−1=14(1−2−6−313−121)A^{-1} = \frac{1}{4}\begin{pmatrix} 1 & -2 & -6 \\ -3 & 1 & 3 \\ -1 & 2 & 1 \end{pmatrix}A−1=411−3−1−212−631
Matrix AAA is singular (non-invertible)