Position From Piecewise Velocity

A hiker embarks on an 8-hour hike. For the first 6 hours, the hiker's velocity is given by y = (2/3)x miles per hour. After 6 hours, the velocity is given by y = -x2 + 12x - 32 miles per hour. Assuming the starting position is x = 0, what is the hiker's position after 8 hours?