#### Answer

$(-1\frac{3}{5},-\frac{4}{5})$

#### Work Step by Step

$3x+4y=-8$
$x=2y$
Using the value for x in the second equation, substitute 2y for x in the first equation.
$3(2y)+4y=-8$ $\longrightarrow$ multiply
$6y+4y=-8$ $\longrightarrow$ add
$10y=-8$ $\longrightarrow$ divide both sides by 10
$10y\div10=-8\div10$ $\longrightarrow$ simplify
$y=-\frac{4}{5}$
Substitute $-\frac{4}{5}$ for y in the second equation.
$x=2(-\frac{4}{5})$ simplify
$x=-1\frac{3}{5}$