Gravatational Potential Energy Question

[SherazSiddiqu]

Homework Statement

How much energy is required to move a satellite from an altitude of 1RE to 3RE?

Homework Equations

1RE= 1 x Radius of the Earth

The Attempt at a Solution

I tried to find the the GPE of the oject but its not working.

 

[kudoushinichi88]

What's the total energy for a satellite in orbit? Then simply find the energy difference between the two orbits.