Chapter 10 - Section 10.2 - Systems of Linear Equations in Several Variables - 10.2 Exercises - Page 697: 12

$x=-\frac{7}{2}$ $y=1$ $z=8$

From the third equation we can express $\frac{1}{2}z=4 \rightarrow z=8$. Then we can substitute $z=8$ into the second equation to find out the value of y. $2y-z=-6\rightarrow 2y-8=-6 \rightarrow y=1$ By substituting $z=8$ into the first equation we get $4x+3z=10\rightarrow4x+24=10\rightarrow x=-\frac{7}{2}$