$\Delta=\frac{1}{2}\left|\begin{array}{ccc}2 & 7 & 1 \\ 1 & 1 & 1 \\ 10 & 8 & 1\end{array}\right|$
$=\frac{1}{2}[2(1-8)-7(1-10)+1(8-10)]$
$=\frac{1}{2}[2(-7)-7(-9)+1(-2)]$
$=\frac{1}{2}[-14+63-2]=\frac{1}{2}[-16+63]$
$=\frac{47}{2}$ square units
$6 \lambda x-3 y+3 z=4 \lambda^2$
$2 x+6 \lambda y+4 z=1$
$3 x+2 y+3 \lambda z=\lambda$
ને ઉકેલ નથી. તો $12 \sum_{\lambda \in S}|\lambda|=........$