$($a$)$ Determine the electric field strength at a point $1\mathrm{.}00cm$ to the left of the middle charge shown in the figure below. $($Enter the magnitude of the electric field only.$)$

N$/$C

$($b$)$ If a charge of $-7\mathrm{.}66C$ is placed at this point, what are the magnitude and direction of the force on it$?$

magnitude

$N$

direction