Solve this

Given: $x+2 y=1$

$3 x+y=4$

$D=\left|\begin{array}{ll}1 & 2 \\ 3 & 1\end{array}\right|=-5$

$D_{1}=\left|\begin{array}{ll}1 & 2 \\ 4 & 1\end{array}\right|=-7$

$D_{2}=\left|\begin{array}{ll}1 & 1 \\ 3 & 4\end{array}\right|=1$

Now,

$x=\frac{D_{1}}{D}=\frac{7}{5}$

$y=\frac{D_{2}}{D}=-\frac{1}{5}$

$\therefore x=\frac{7}{5}$ and $y=-\frac{1}{5}$