MAT 117 UMBC Write the Range of ? Using Interval Notation Algebra Questions

Objective B
1. An adventurer has reached the top of a mountain, which is 14,982 feet above sea level.  After resting, the
adventurer begins climbing down the mountain.  Four days later, the adventurer reaches the height of 9,675 feet
above sea level.
a. [2 pts] Determine the average rate of change (slope) of the adventurer’s height above sea level with respect to
the time spent climbing down the mountain.
b. [2 pts] If ? is the number of days since the adventurer began her descent and ?(?) is the number of feet the
adventurer is above sea level, find the equation of the line through these two points.
c. [2 pts] Assuming ?(?) is a linear function, use the equation to predict the height of the adventurer above sea
level after six days since descending from the summit of the mountain.
2. Michelle asks her husband to build a pen for her chickens. Three of the sides will be built with mesh fencing, while
the fourth side will back up to the east side of her house.  She wants the enclosed area to be 400 square feet.  The
cost of the fence meshing will be $4.18 per foot and the pen will also need 4 corner posts costing $9.50 each.
a. [6 pts]  Let ? be the length of the side of the chicken coop that backs up to the east side of the house.  Write a
function ?(?), for the price of the materials for the pen in terms of x.  Simplify your answer.
b. [3 pts]  Use your calculator to find the dimensions of the pen that costs the least. Set your window with:
0 ???80 and 10 ???400, and round your answer to 2 decimal places. (Insert your graph here. You may
hand draw the graph or insert an image of the graph from Desmos)
c. [1 pt]  What is the total cost of the pen?  Round to dollars and cents.
3. Consider the piecewise defined function f:
?(?) = {0.75??0.25 ?4 ??< 24 2 ??< 4?0.54?+ 2 4 ???6
a. [3 pts]  Graph the  ?(?). (Insert your graph here. You may hand draw the graph or insert an image of the graph
from Desmos)
b. [2 pts]  Write the domain of ? using interval notation
c. [2 pts] Write  the range of ? using interval notation
d. [2 pts]  On what interval(s) is ?(?) decreasing?