Gravitational Potential Energy (GPE) is the energy of a mass due to its position within a gravitational field.
On a larger scale however,
GPE can be defined as the work done to move an object from infinity to a point within the gravitational field.
Ep=-(Gm1m2)/r
Where: Ep: Electrical Potential Energy (Joules)
G=6.67x10-11
m1m2: mass of objects
r: distance (km)
Ep at ∞> Ep at x (x,any point)
But Ep at ∞=0
Then,Ep at x<0
∴Ep=-(Gm_1 m_2)/r
this is what i wrote for it... but it simply is what's stated in the dotpoint :L