# How do you solve the following system?: x + 3y = -3 , y=-x + 12

Mar 22, 2018

$\left(\frac{39}{2}\right) , \left(- \frac{15}{2}\right)$

#### Explanation:

$x + 3 y = - 3$ and $y = - x + 12$

we can substitute the value of y of the second equation in the first equation so we get,

$x + 3 \left(- x + 12\right) = - 3$

On simplification

$x - 3 x + 36 = - 3$

We get that $x = \frac{39}{2}$

Substituting it in either of the initial equations and solving for y, we get $y = - \frac{15}{2}$

So the solution to the given pair of equations is $x = \frac{39}{2}$ and $y = - \frac{15}{2}$