Part A:
Expression: 21 = 8h + 179
Part B:
21 = 8h + 179
h = - 19
Move 179 to the other side by subtracting 179 from both sides.
21 - 179 = -158
-158 = 8h
Then, divide both sides by 8 to get the feet descended per hour.
-158/8 = -19
h = -19
Therefore, Luther and Nicole descend approximately 19 feet per hour.