Please help me with this.

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

Find the equation of the trend line (line of best fit). show your work i'm using the points (34,76) (42,91)

Which ordered pair (c,d) is a solution to the given system of linear equations- c+2d=13 -9c-4d=-15