Two charges are located on the $x$ axis: $q_1=+5\mathrm{.}0C$ at $x_1=+4\mathrm{.}1cm,$ and $q_2=+5\mathrm{.}0C$ at $x_2=-4\mathrm{.}1cm.$ Two other charges are located on the $y$ axis: $q_3=+2\mathrm{.}8C$ at $y_3=+4\mathrm{.}3cm,$ and $q_4=-9\mathrm{.}4C$ at $y_4=+6\mathrm{.}8cm.$ Find $($a$)$ the magnitude and $($b$)$ the direction of the net electric field at the origin.

$($a$)$ Number Units

$($b$)$ The net electric field points