(a) $2x + y − 2z = 0 \\ x − y − 4z = −3 \\ 3x − 6z = −3$

$2\left(x − y − 4z\right) → 2x − 2y − 8z = −6$

(b) $3x + 2y + 2z = −1 \\ 5x − 6z = −7$

Now use equations (a) and (b) to solve for x and z, and use those values to solve for y.

$\left(-2, 3, -\frac{1}{2}\right)$