Find the inverse function of that problem!

How do i do this using elimination 2x+3y=12 x-y=6

Aman steps out of a plane at a height of 4,000m above the ground falls 2,000m very quickly and then opens his parachute and slowly falls the remaining 2000m to the ground what height above the ground would be the best choice for a reference point

When only separate discreet points are graphed it is called?