## College Algebra (6th Edition)

$\left\{\begin{array}{l} 2x-z=6\\ 3y=9\\ x+y=5 \end{array}\right.$
The product on the LHS is between a $3\times\underline{3}$ and a $\underline{3}\times$1 matrix, resulting in a $3\times 1$ matrix: $\left[\begin{array}{l} 2x+0y-1z\\ 0x+3y+0z\\ 1x+1y+0z \end{array}\right]$ Equating matrices, (equating corresponding elements), we have the system $\left\{\begin{array}{l} 2x-z=6\\ 3y=9\\ x+y=5 \end{array}\right.$