Unit 2 MCQ A + B, Difficult Questions (I got wrong ):

The number of bacteria in a dish is 1150 at time t=0 hours. The number of bacteria in the dish doubles every 3 hours. If the function B gives the number of bacteria in the dish at time t hours for t≥0, which of the following could define B(t) ?

1150 times 2^(t/3)

The function f is given by f(x) = log^2x. If g(x) = f^-1(x), for what value of k does g(k) = 8 ?

3

​ The function g is given by g(x) = 4 times 2^(3+x). The function g can also be expressed as which of the following?

32 times 2^3

The first term of a geometric sequence is 2/3. The next three terms are 1/2, 3/8, and 9/32. What is the tenth term of the sequence?

6,561/131,072

​The function ℎ is given by ℎ(x) = a times b^(-x), where a<0 and b>1. Which of the following describes ℎ and its graph in the xy-plane?

ℎ is increasing, and the graph of ℎ is concave down.

​ The expression 8^(x+7) is part of an equation involving other exponential expressions with base e. Which of the following is equivalent to 8^(x+7) and is therefore more useful in solving the equation?

e^(ln 8)(x) + 7

​Students in a statistics class examined individual student test scores for a large group of students. Each test score is paired with the reported time the student spent studying. The class observed that when study time doubled, test scores generally increased by 5 points. For example, a student who studied 2n minutes generally scored 5 points higher than a student who studied n minutes. For nonzero constants a and b, which of the following types of functions is most useful in modeling test scores as a function of time t studied, in minutes?

f(t) = a times b^t