#### Answer

We can verify the equations by substituting in the given $x$, $y$ and $z$ values and then check if the equalities still hold.
Here: $3x+3y+2z=3(1)+3(-1)+2(2)=3+(-3)+4=4$, which is correct.
$x-y-z=1-(-1)-2=0$, which is correct.
$2-3z=2(-1)-3(2)=-2-6=-8$, which is correct.