Answer
$$z=\frac{1}{3},\:y=-4,\:x=\frac{1}{2}$$
Work Step by Step
Solving the system of equations using substitution, we find:
$$ 2\cdot \frac{-4-\left(9z-7\right)+3z}{2}-\left(9z-7\right)+6z=7\\ z=\frac{1}{3} \\ y=9\cdot \frac{1}{3}-7=-4 \\ x=\frac{-4-\left(-4\right)+3\cdot \frac{1}{3}}{2}=\frac{1}{2}$$
