UMUC Asia
MATH107
Prof. Andrew Won
Jessica L Hampton
Quiz 7
Q7.1. Graph 𝑓(𝑥) = √x − 8 and use the graph to determine whether the
function is one-to-one. If the function is one-to-one, find 𝑓 −1
3
Q7.2. An organization determines that the cost per person of chartering a
bus is given by 𝐶(𝑥) =
100+5𝑥
𝑥
, where 𝑥 is the number of people in the group
and 𝐶(𝑥) is in dollars. Determine 𝐶 −1 (𝑥) and explain what it represents.
Show graph of C(x) and its inverse function C-1(x).
Q7.3. The value of a stock is given by the function V(t) = 58(1 − e−1.1t ) + 20,
where 𝑉 is the value of the stock after time 𝑡, in months. Find
𝑉(1), 𝑉(6), and 𝑉(12). Graph 𝑉(𝑡).
Q7.4. In chemistry, the pH of a substance is defined by pH = −log[H + ],
where H+ is the hydrogen ion concentration, in moles per liter. Graph pH(H).
Then find the pH of each substance.
a) Pineapple juice 1.6x10-4
b) Mouthwash 6.3x10-7
c) Hair rinse 0.0013
Q7.5. Solve and graph log 2 (𝑥 − 3) ≥ 4.