PLZ HELP ON THIS QUESTION

Quick translate "x is 12 units from 20" into an equation. what are the values of x being described? if you can answer any of my other questions that'd be great too

What are the coordinates of the midpoint of ab? ,1/2) /2,-1) ,-3/2) /2,-2)

Richard save $32 in march he saved $48 in april and $38 in may then richard spent $113 on a keyboard how much money does richard have left