In Example $6\mathrm{.}4-2,$

$($a$)$ Determine the surplus capacities for al the arcs.

$($b$)$ Determine the amount of flow through nodes $2,3,$ and $\mathrm{.}4$

$($c$)$ Can the network flow be increased by increasing the capacities ni the directions $3->5$ and $4->5?$