3. Jeremy stands on the edge of a river and throws a rock into the water. The rock leaves his hands at a height of 5 feet above the water. It moves upward and then
down before splashing into the center of the river. The rock is 20 feet in the air
when it is 10 feet away from Jeremy. The rock reaches the highest point along its
path when it is horizontal distance of 20 feet from his hand and 25 feet above the
water.
Write a function h to represent the height of the rock in terms of its distance, d,
from Jeremy's hand.