How do you solve 6y - x = -36 and y = -3x using substitution?

Jun 5, 2016

$x = \frac{36}{19}$
$y = - \frac{108}{19}$

Explanation:

if $y = - 3 x$ let's substitute in the first equation, so:
$6 \left(- 3 x\right) - x = - 36$
then
$- 18 x - x = - 36$
$- 19 x = - 36$
$x = \frac{36}{19}$

and
$y = - 3 \left(\frac{36}{19}\right)$
$y = - \frac{108}{19}$