# How do you solve the following system: y = 3x – 12, x = 4 – 2y ?

Apr 21, 2018

$x = 4 , y = 0$

#### Explanation:

First substitute $x = 4 - 2 y$ into $y = 3 x - 12$
Then the equation becomes:
$y = 3 \left(4 - 2 y\right) - 12$
$y = 12 - 6 y - 12$
bring all the $y$ to the LHS:
$7 y = 0$
$y = 0$
Then substitute $y = 0$ into $x = 4 - 2 y$
$x = 4 - 2 \left(0\right)$
$x = 4$