Question: Find the Pivot element for

\(\begin{aligned} & \,{{x}_{1}}\,\,\,\,\,{{x}_{2}}\,\,\,\,\,\,\,{{s}_{1}}\,\,\,\,\,\,\,{{s}_{2}} \\ & \left[ \begin{matrix} 1 & \frac{1}{2} & \frac{1}{4} & 0 & 30 \\ 0 & 1 & -\frac{1}{2} & 1 & 20 \\ 0 & -1 & 1 & 0 & 120 \\ \end{matrix} \right] \\ \end{aligned}\)