Answer
$(2,2)$
Work Step by Step
Given system is-
$x +y$ = $4$ __ eq.1
$-x +y$ = $0$ __ eq.2
Adding both the equations-
$x +y-x +y$ = $4+0$
i.e. $2y$ = $4$
i.e. $y$ = $\frac{4}{2}$ = $2$
Substituting for $y$ in eq.1
$x +2$ = $4$
i.e. $x$ = $4-2$ =$2$
Thus $(2,2)$ is the solution of given system.