The tide, or depth of the ocean near the shore, changes throughout the day. The water depth

(in feet) of a bay can be modeled by

where

is the time in hours, with

corresponding to 12:00 A.M.

(a) Algebraically find the times at which the high and low tides occur.

**How would I do this? Just solve for ** **? Wouldn't I just get one answer? I need two, one for the high and one for the low.**
(b) Algebraically find the time(s) at which the water depth is 3.5 feet.

**Just ** **for 3.5 and solve right? I have one question though...how would you determine ** **algebraically?**
I have also attached a picture of the original problem.