### Home > INT3 > Chapter 12 > Lesson 12.1.2 > Problem12-28

12-28.

Solve the system of equations below. What subproblems did you need to solve?

$x + 2y = 4$
$2x − y = −7$
$x + y + z = −4$

Use the first two equations to solve for $x$ and $y$ using the Elimination Method.

$−2\left(x + 2y\right) = −2\left(4\right)$

$2x − y = −7$

Now that you know $x$ and $y$, how can you find $z$?

$x = −2$, $y = 3$, $z = −5$