#### Answer

(4,2)

#### Work Step by Step

$5x-y=18$
$y=\frac{1}{2}x$
Substitute $\frac{1}{2}x$ for y in the first equation.
$5x-\frac{1}{2}x=18$ $\longrightarrow$ simplify
$4\frac{1}{2}x=18$ $\longrightarrow$ divide both sides by 4.5
$4\frac{1}{2}x\div 4\frac{1}{2}=18\div4\frac{1}{2}$ $\longrightarrow$ simplify
$x=4$
Substitute 4 for x in the second equation.
$y=\frac{1}{2}(4)$ $\longrightarrow$ simplify
$y=2$