$6\mathrm{.}43.$ If $($W$)/($L$)=(10)/(0\mathrm{.}18)$ and $\backslash$lambda $=0,$ determine the operating point of M$\_(1)$ in each circuit depicted in Fig. $6\mathrm{.}56.($a$)$

$($b$)$

$($c$)$