# How do you solve the following system using substitution?: y=x-4, y=2x

Jun 11, 2018

$x = - 4 , y = - 8$

#### Explanation:

Substitute eq2 in eq1 :
$\text{ }$
$2 x = x - 4$
$\text{ }$
$\Rightarrow 2 x - x = - 4$
$\text{ }$
$\Rightarrow x = - 4$
$\text{ }$
Substitute the value of $x$ in eq2
$\text{ }$
$y = 2 x = 2 \left(- 4\right) = - 8$
$\text{ }$
$\therefore x = - 4 , y = - 8$