Answer
$$z=-2,\:y=-1,\:x=1$$
Work Step by Step
Solving the system of equations using substitution, we find:
$$ 5\cdot \frac{1+\frac{-z-7}{5}-z}{2}-\frac{-z-7}{5}+3z=0 \\ z=-2 \\ y=\frac{-\left(-2\right)-7}{5}=-1 \\ x=\frac{1-1-\left(-2\right)}{2}=1$$
