## Algebra and Trigonometry 10th Edition

$\begin{bmatrix} 1 & 1 \\ 3 & 4 \end{bmatrix}$
The general form of a matrix of order $2 \times 2$ is: $Det \ A \begin{bmatrix} p & q \\ r & s\end{bmatrix}=ps-qr$ Write the augmented matrix with identity matrix. $\begin{bmatrix}1 & -1/4 \\ 0 & 1/4 \end{bmatrix}$ Now, add row $2$ to row $1$, then multiply row $2$ by $4$. $\begin{bmatrix} 1 & 1 \\ 3 & 4 \end{bmatrix}$ Our answer is: $\begin{bmatrix} 1 & 1 \\ 3 & 4 \end{bmatrix}$