The forces F$1,$ F$2,...,$ Fn acting at the same point P are said to be in equilibrium if the resultant force is zero, that is$,$ if F$1+$ F$2++$ Fn $=0.$

F$1=$

$3,4$

$,$F$2=$

$6,2$

$,$F$3=$

$9,6$

$$

$($a$)$ Find the resultant force acting at P$.$

$($b$)$ Find the additional force required $($if any$)$ for the forces to be in equilibrium. $($If an answer does not exist, enter DNE.$)$