17. The bottom of a river makes a V-shape that can be modeled with the absolute value function,
where d is the depth of the river bottom (in feet) and h is the horizontal
d(h)=h-240-48,
distance to the left-hand shore (in feet).
A ship risks running aground if the bottom of its keel (its lowest point under the water) reaches
down to the river bottom. Suppose you are the harbormaster and you want to place buoys where
the river bottom is 30 feet below the surface. How far from the left-hand shore should you place
the buoys?
