Which group has a greater median ? Please answer fast

Can someone me with the property questions for 12 13 and 14 plz

How do you figure out which order to do two step equations in? like which thing do you subtract/add/multiply/divide first? i understand that you do the opposite of whatever's shown on the opposite side, but when?

Technical improvements catechnical improvements cause production costs to decline, which causes to increase and prices to decreased unemployment causes consumer incomes to use production costs to decline, which causes to increase and prices to decreased unemployment causes consumer incomes to