Where Should the Third Mass Be Placed to Experience No Net Gravitational Force?

[sheri1987]

Homework Statement

M1 is a spherical mass (43.0 kg) at the origin. M2 is also a spherical mass (11.8 kg) and is located on the x-axis at x = 52.8 m. At what value of x would a third mass with a 16.0 kg mass experience no net gravitational force due to M1 and M2?

Homework Equations

F= G(m1 * m2)
r^2

The Attempt at a Solution

G = 6.67*10-11, m1 = 43, m2= 11.8 and r^2 = 52.8 ...I plugged all of this into solve for F, then I think I have to use this equation again and multiply the top by a m3 and solve for x using the F I found previous...is this right, if not could you help me out? Thanks

 

[learningphysics]

suppose m3 is located at some value x that is between 0 and 52.8m.

What is the force m1 exerts on m3? What is the force m2 exerts on m3? Take right to be positive... left to be negative.