## Cramer rule

### Task number: 2605

By using Cramer rule solve the following systems of equations:

#### Variant 1

\(\mathbf A\mathbf x=\mathbf b\) over \(\mathbb R\) for

\( \mathbf A= \begin{pmatrix} 1 & 2 & -2 & 2 \\ 2 & 3 & 1 & 1 \\ -1 & 2 & 3 & -1 \\ 1 & -1 & 1 & -1 \\ \end{pmatrix} \) and \( \mathbf b = \begin{pmatrix} -2 \\ 2 \\ -1 \\ 4 \end{pmatrix} \).

#### Variant 2

over \(\mathbb Z_5\):

\[\begin{eqnarray*} 2x + y + 4z &=& 1 \\ 3x + y + 4z &=& 2 \\ 2x + 4y + 2z &=& 3 \end{eqnarray*}\]