Answer
given,
mass of object
m₁ = 130 Kg
m₂ = 430 Kg
distance between them = 0.3 m
a) net force when 35 kg is place in between them
now,
Direction of force will be toward the mass of 430 Kg
b) position where force will be zero
solving the above equation
x = 0.1936 m
the distance of third mass will be at x = 0.1936 m from 430 Kg mass.