Gauss law and nonconducting spherical shells

[nogoodaatphys]

Homework Statement

there are two nonconducting spherical shells fixed in place. shell 1 has uniform surface charge density 6.0 uC/m^2 on its outer surface and radius 3.0cm. shell 2 has uniform surface charge density 4.0 uC/m^2 on its outer surface and radius 2.0cm. the shell centers are separated by l=10cm. in unit vector notation, what is the net electric field at x=2.0cm.
There is a picture that shows shell 1 with it's center at the origin, and shell 2 centered at (10,0) (because l=10)

Homework Equations

gauss' law, but not sure exactly what form.

The Attempt at a Solution

Well I'm unsure what to do, but I solved for the electric field created by both shells.
Shell 1=6*10^7
Shell 2= 9*10^7 (ignoring the units for the moment)

ok so I have that, but I have no idea how to determine the net field at any given point. can anyone help me get started? Thanks.

 

[gabbagabbahey]

Well, the first step would be to put your two individual electric fields into unit vector notation (they are vector fields after all!), after that...what does the superposition principle tell you?