# How do you solve the system x+y=4, 2x+3y=0?

Jun 24, 2017

Rearrange the equations and solve by substitution.

$x = - y + 4$ Let this be equation 1.

$2 x + 3 y = 0$ Let this be equation 2.

Substitute equation 1 into equation 2:

$2 \left(\textcolor{red}{- y + 4}\right) + 3 y = 0$

$- 2 y + 8 + 3 y = 0$

$y = - 8$

Substituting $y = - 8$ into equation 1,

$x = - \left(\textcolor{red}{- 8}\right) + 4$

$x = 12$