On a windy morning, a hot air balloon starts rising and flying away from the top of a hill. The altitude, h, in feet, of the balloon x hours after starting its ascent from the hill, can be modeled by the function:
Part B: There is a positive and negative x intercept for this function. What is the positive x-intercept?
Explain what this x-intercept represents in the given situation.

h(x)=-16x2+64x+80