Linda.
We need to integrate this function over the interval 0-6 seconds.
∫06 -t2+6 dt
-t3/3 + 6t |60
-(63)/3 + 6(6) - [-(03)/3 + 6(0)]
-216/3 + 36 - 0
-72+36 = -36
Over a 6 second interval, this object will be displaced by -36 feet.