What is the total energy of a system of two masses at an infinite distance from each other?

The masses $m$ in figures $(A)$ and $(B)$ are identical. The gravitational potential energy in the two cases are $U_A$ and $U_B$. Then

If $g$ is the acceleration due to gravity on the earth's surface,the gain in the potential energy of an object of mass $m$ raised from the surface of the earth to a height equal to the radius $R$ of the earth is

Taking the gravitational potential at a point at an infinite distance away as zero,the gravitational potential at a point $A$ is $-5 \, unit$. If the gravitational potential at a point at an infinite distance away is taken as $+10 \, units$,the potential at point $A$ is ......... $unit$.

Four particles,each of mass $M$,are located at the vertices of a square with side $L$. The gravitational potential due to this system at the centre of the square is:

$A$ body of mass $m$ is taken from the Earth's surface to a height $h$ equal to twice the radius of the Earth $(R_e)$. The increase in potential energy will be: (where $g$ is the acceleration due to gravity on the surface of the Earth)