Answer
$\left[\begin{array}{lll}
1 & 4 & -1\\
1 & 3 & -2\\
2 & 7 & -5
\end{array}\right]\left[\begin{array}{l}
x\\
y\\
z
\end{array}\right] $=$\left[\begin{array}{l}
3\\
5\\
12
\end{array}\right]$
Work Step by Step
Coefficient matrix A=$\left[\begin{array}{lll}
1 & 4 & -1\\
1 & 3 & -2\\
2 & 7 & -5
\end{array}\right]$
Constant matrix B=$\left[\begin{array}{l}
3\\
5\\
12
\end{array}\right]$
Matrix equation:
$AX=B$
$\left[\begin{array}{lll}
1 & 4 & -1\\
1 & 3 & -2\\
2 & 7 & -5
\end{array}\right]\left[\begin{array}{l}
x\\
y\\
z
\end{array}\right] $=$\left[\begin{array}{l}
3\\
5\\
12
\end{array}\right]$