Answer
$6.8\times 10^5\frac{N.m^2}{C}$
Work Step by Step
We can find the electric flux as
$\phi=\frac{q}{\epsilon{\circ}}$
$\implies \phi=\frac{q_1+q_2+q_3}{\epsilon_{\circ}}$
We plug in the known values to obtain:
$\phi=\frac{(3.2+6.9-4.1)\times 10^{-6}}{8.85\times 10^{-12}}$
$\phi=6.8\times 10^5\frac{N.m^2}{C}$
