Answer
$\left[\begin{array}{rr}
2 & 1\\
-1 & 0
\end{array}\right]\left[\begin{array}{l}
x\\
y
\end{array}\right]=\left[\begin{array}{l}
7\\
9
\end{array}\right]$
Work Step by Step
Define matrices
A is the coefficient matrix (left-hand sides of the equations)
X is the column matrix consisting of the unknowns ,
B is the column matrix consisting of the right-hand sides of the equations
$A=\left[\begin{array}{ll}
2 & 1\\
-1 & 0
\end{array}\right],\quad X=\left[\begin{array}{l}
x\\
y
\end{array}\right] \quad B=\left[\begin{array}{l}
7\\
9
\end{array}\right]$
The given system of linear equations translates to AX=B
$\left[\begin{array}{ll}
2 & 1\\
-1 & 0
\end{array}\right]\left[\begin{array}{l}
x\\
y
\end{array}\right]=\left[\begin{array}{l}
7\\
9
\end{array}\right]$
