In the above diagram, where do the 3/5 and 2/5 come from? Also, how are the (e sub g)$\ce{e_g}$ orbitals degenerate with each other?
I got the image from https://ocw.mit.edu/courses/chemistry/5-111sc-principles-of-chemical-science-fall-2014/unit-iv-transition-metals-oxidation-reduction-reactions/MIT5_111F14_Lecture28.pdf