posted by Jeff .
In the figure below, two point particles are fixed on an x axis separated by a distance d. Particle A has mass mA and particle B has mass 2.00mA. A third particle C, of mass 90.0mA, is to be placed on the x axis and near particles A and B. In terms of distance d, at what x coordinate should C be placed so that the net gravitational force on particle A from particles B and C is zero?
I know the f=gm1m2/r^2 equation but if the net force of particle A is 0 then im getting r=0.