## Precalculus (6th Edition) Blitzer

The required value is $x=2,y=-1$.
Add both equations to obtain, \begin{align} & x+y+\left( x-y \right)=1+3 \\ & 2x=4 \\ & x=2 \end{align} Substitute the value of $x=2$ in the first equation and solve for y as follows: \begin{align} & 2+y=1 \\ & y=-1 \end{align} Thus, the value of $x=2$ and $y=-1$.