Does y vary directly as x in this function? y= -3x+4

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

Brook states that the distance on the line is 4 units. caleb states that the whole line does not have a distance because it continues on forever. vivian states that the line is 6 units long. which distance did brook measure? which distance did vivian measure?

In two or more complete sentences describe how to determine the appropriate model for the set of data, (1,1), (3,2), (6,3), (11,4).