#### Answer

$(1\frac{1}{3},-1\frac{1}{3})$

#### Work Step by Step

$2x-y=4$
$y=-x$
Substitute -x for y in the first equation.
$2x-(-x)=4$ $\longrightarrow$ simplify
$3x=4$ $\longrightarrow$ divide both sides by 3
$3x\div3=4\div3$ $\longrightarrow$ simplify
$x=1\frac{1}{3}$
Substitute $1\frac{1}{3}$ for x in the second equation.
$y=-1\frac{1}{3}$