A rock is tossed off a balcony. Its height (in feet) is given by the formula h
(
t
)
=
−
16
t
2
+
7.7
t
+
130
, where
t
is measured in seconds.
How long will it take the rock to hit the ground?

Awater truck is filling a swimming pool. the equation that represents this relationship is y=19.75x where y is the number of gallons of water in the pool and x is the number of minutes the truck has been filling the pool.