Chapter 4.2, Problem 6E

In Exercises 1–6, determine the next pivot element for the tableau.

$\begin{array}{l}\begin{array}{cccccc}x& y& u& v& w& M\end{array}\\ \left[\begin{array}{ccccccc}\frac{1}{2}& 0& \frac{1}{2}& 0& 0& 0& 7\\ \frac{1}{2}& 0& -\frac{1}{2}& 1& 0& 0& 2\\ 2& 0& -1& 0& 1& 0& 10\\ -\frac{1}{2}& 0& \frac{3}{2}& 0& 0& 1& 21\end{array}\right]\end{array}$