If $x\left[\begin{array}{l}2 \\ 3\end{array}\right]+y\left[\begin{array}{c}-1 \\ 1\end{array}\right]=\left[\begin{array}{c}10 \\ 5\end{array}\right]$, find values of $x$ and $y$.
$x\left[\begin{array}{l}2 \\ 3\end{array}\right]+y\left[\begin{array}{c}-1 \\ 1\end{array}\right]=\left[\begin{array}{l}10 \\ 5\end{array}\right]$
$\Rightarrow\left[\begin{array}{l}2 x \\ 3 x\end{array}\right]+\left[\begin{array}{c}-y \\ y\end{array}\right]=\left[\begin{array}{l}10 \\ 5\end{array}\right]$
$\Rightarrow\left[\begin{array}{l}2 x-y \\ 3 x+y\end{array}\right]=\left[\begin{array}{l}10 \\ 5\end{array}\right]$
Comparing the corresponding elements of these two matrices, we get:
2x − y = 10 and 3x + y = 5
Adding these two equations, we have:
5x = 15
$\Rightarrow x=3$
Now, $3 x+y=5$
$\Rightarrow y=5-3 x$
$\Rightarrow y=5-9=-4$
$\therefore x=3$ and $y=-4$