(x？ +5)/2=(x？ -3+8)×5/5/2=(x？ -3+8)/5×(5/2)=(x？ -3)/5+8/5×(5/2)=(x？ -3)/5+4

In short, the purpose is to make "the part after 1+ in brackets" and "the index outside brackets" into reciprocal forms.

I sent you pictures and words. I don't know if you can understand them.