02. i) (Thinking: (4 marks) The elevation of a hiking trail is modelled by the function b(x) = 2x + 3x2 - 17x + 12, where / is the height measured in metres above sea level and x is the horizontal position from a ranger station measured in kilometres. If x is negative, the position is to the west of the station, and if x is positive, the position is to the east. Since the trail extends 4.2 km to the west of the ranger station and 4 km to the east, the model is accurate where xe [- 4.2, 4]. At what distances from the ranger station is the trail above sea level