Solve this

Given : $2 x-y=1$

$7 x-2 y=-7$

Using Crammer's Rule, we get

$\mathrm{D}=\mid 2 \quad-1$

$7-2 \mid=-4+7=3$

$\mathrm{D}_{1}=\mid 1=-1$

$-7-2 \mid=-2-7=-9$

$\mathrm{D}_{2}=\mid 2 \quad 1$

$7-7 \mid=-14-7=-21$

Now,

$\mathrm{x}=\frac{\mathrm{D}_{1}}{\mathrm{D}}=\frac{-9}{3}=-3$

$\mathrm{y}=\frac{\mathrm{D}_{2}}{\mathrm{D}}=\frac{-21}{3}=-7$

$\therefore \mathrm{x}=-3$ and $\mathrm{y}=-7$