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MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
The loudness of a sound can be approximated by the formula d = 10 log10 I
I0, where d is the
number of decibels. The higher the value of d, the louder the sound. Find the number of decibels
when I =100 and I0= 1.
Write the logarithmic equation in its equivalent exponential form.
Write the expression as the sum or difference of logarithms.
1
4(logb x9+logb b5–logb y7)
Evaluate the function for the given value. Round to the nearest thousandth.
Write the exponential equation in its equivalent logarithmic form.
Solve . Round the answer to three decimal places.
Write the expression as the sum or difference of logarithms.
7logb m + 3logb p – 2logb n
7logb m + 3logb p +2logb n
Write the expression as a single logarithm.
Use a calculator to approximate the logarithm to four decimal places.
log4 (x – 8) +log4 (x – 8) = 1
Evaluate the function for the given value.
Solve . Round the answer to three decimal places.
Write the logarithmic equation as an exponential equation.
A motorized scooter is purchased for $4700. Its value each year is about 77% of the value the
preceding year. Its value, in dollars, after t years is given by the exponential function V(t) =4700
(0.77)t. Find the value of the scooter after 7 years.
Write the exponential equation in its equivalent logarithmic form.
log4(x – 4) +log4(x – 10) =2
Provide an appropriate response.
Evaluate the function for the given value.
f(x) =2x +3+7; f(2)
Use a calculator to approximate the logarithm to four decimal places.
Evaluate the function for the given value.
Write the expression as a single logarithm.
Write the exponential equation in its equivalent logarithmic form.
Provide an appropriate response.
Write the exponential equation in its equivalent logarithmic form.
Provide an appropriate response.
Write the exponential equation in its equivalent logarithmic form.
Evaluate the function for the given value. Round to the nearest thousandth.
Write the expression as the sum or difference of logarithms.
Determine whether the function is a polynomial function, a rational function, a radical function, or an exponential
function.
Write the logarithmic equation in its equivalent exponential form.
Use a calculator to approximate the logarithm to four decimal places.
Write the logarithmic equation as an exponential equation.
Write the expression as a single logarithm.
Two bacteria are placed in a petri dish. The population will triple every day. The formula for the
number of bacteria in the dish on day t is N(t) =2(3)t, where t is the number of days after the two
bacteria are placed in the dish. How many bacteria are in the dish five days after the two bacteria
are placed in the dish?
Write the expression as a single logarithm.
How long will it take for the population of a certain country to double if its annual growth rate is
2.4%? Round to the nearest year. Use the exponential growth model P(t) =P0ekt.
Provide an appropriate response.
Write the expression as the sum or difference of logarithms: log3x4
3y4
Write the expression as a single logarithm.
Provide an appropriate response.
Write the exponential equation in its equivalent logarithmic form.
The height in feet of males in a certain ethnic group is approximated by H =2.7 + 2 log t
1.2 where
t is the boy’s age and 1
t
18. Use the properties of logarithms to write the expression on the right
side of the equation so that it does not contain the logarithm of a quotient.
H =2.7 + 2log t – log 1.2
H =2.7 + 2(log t + log 1.2)
H =2.7 + 2log t + log 1.2
H =2.7 + 2(log t – log 1.2)
Provide an appropriate response.
Use the power property to rewrite the expression.
Provide an appropriate response.
Solve . Round the answer to three decimal places.
Use a calculator to approximate the logarithm to four decimal places.
Write the expression as the sum or difference of logarithms.
Write the logarithmic equation in its equivalent exponential form.
Write the expression as the sum or difference of logarithms.
Use the power property to rewrite the expression.
Use a calculator to approximate the logarithm to four decimal places.
log5 (x +3) +log5 (x –3) =2
Write the logarithmic equation in its equivalent exponential form.
Use a calculator to approximate the logarithm to four decimal places.
How long will it take a sample of radioactive substance to decay to half of its original amount, if it
decays according to the function A(t) =600e–0.163t, where t is the time in years? Round to the
nearest hundredth.
Evaluate the function for the given value. Round to the nearest thousandth.
Write the expression as the sum or difference of logarithms.
Write the expression as a single logarithm.
Evaluate the function for the given value. Round to the nearest thousandth.
Solve . Round the answer to three decimal places.
Provide an appropriate response.
Write the expression as a single logarithm.
Write the expression as the sum or difference of logarithms.
Provide an appropriate response.
Write the exponential equation in its equivalent logarithmic form.
Use the power property to rewrite the expression.
Write the expression as a single logarithm.
Write the expression as a single logarithm.
Sun Woo Kim invested $2000 at 7% compounded monthly. How much will be in the account in 5
years? Round to the nearest cent.
Provide an appropriate response.
Evaluate, rounding to four decimal places: log395.65
Evaluate the function for the given value. Round to four decimal places.
f(x) =ex +3; f(4)
Evaluate the function for the given value.
Write the expression as the sum or difference of logarithms.
83x =5x + 1 (Round to the nearest thousandth.)
Provide an appropriate response.
Write the expression as a single logarithm: 6logb (x –10) –11 logb x
Use a calculator to approximate the logarithm to four decimal places.
Solve . Round the answer to three decimal places.
Write the expression as the sum or difference of logarithms.
Coyotes are one of the few species of North American animals with an expanding range. The future
population of coyotes in a region of Mississippi can be modeled by the equation
P =55 +16 · ln(13t + 1), where t is time in years. Use the equation to determine approximately how
long it will take the population to reach 160. Round to the nearest year.
Write the expression as a single logarithm.
Write the expression as a single logarithm.
Solve . Round the answer to three decimal places.
The half–life of a certain radioactive substance is 15 years. Suppose that at time t = 0 , there are 30 g
of the substance. Then after t years, the number of grams of the substance remaining will be N(t) =
30 1
2t/30. How many grams of the substance will remain after 120 years? Round to the nearest
tenth.
Use a calculator to approximate the logarithm to four decimal places.
The number of bacteria growing in an incubation culture increases with time according to
B(x) =4500(4)x, where x is time in days. Find the number of bacteria after 5 days. What was the
initial number of bacteria in the incubation culture?
The hydrogen potential, pH, of a substance is defined by pH = –log10 [H+], where the hydrogen
ion concentration, [H+], is measured in moles per liter. Find the hydrogen ion concentration of a
solution whose pH is 7.2.
0.8573325 moles per liter
6.31 × 10–8moles per liter
–0.8573325 moles per liter
1.58 × 107moles per liter
Write the exponential equation in its equivalent logarithmic form.
Write the expression as the sum or difference of logarithms.
The population of a particular city is increasing at a rate proportional to its size. It follows the
function P(t) = 1 + ke0.09t where k is a constant and t is the time in years. If the current population
is 30,000, in how many years is the population expected to be 75,000? Round to the nearest year.
The loudness of a sound can be approximated by the formula d = 10 log I
I0, where d is the number
of decibels. The higher the value of d, the louder the sound. Find the number of decibels when
I =10,000 and I0= 1.
Use the power property to rewrite the expression.
Determine whether the function is a polynomial function, a rational function, a radical function, or an exponential
function.
Write the expression as the sum or difference of logarithms.
What is the intensity in watt/m2 of a noise measured at 70 decibels? D = 10 log10(S/S0), where S0 is
10–12 watt/m2. Round to two decimal places when necessary.
Write the exponential equation in its equivalent logarithmic form.
Write the expression as a single logarithm.
6log2 (2x + 8) + 3log2(4x – 6)
log2 [(2x + 8)6+(4x – 6)3]
Use a calculator to approximate the logarithm to four decimal places.
Determine whether the function is a polynomial function, a rational function, a radical function, or an exponential
function.
The level of a sound in decibels (db) is determined by the formula
sound level = 10 · log(I ×1012) db, where I is the intensity of the sound in watts per square meter.
What is the intensity of a noise measured at 83 db? Express the answer in scientific notation,
rounded to two decimal places.
The length of the side of the fence surrounding the square garden shown in the following diagram
can be found by solving the equation log25 x =1
2. What does the base in the equation represent?
The area enclosed by the fence
The square of the length of the side of the fence
The perimeter surrounded by the fence
Determine whether the function is a polynomial function, a rational function, a radical function, or an exponential
function.
The volume of space in a landfill, measured in meters cubed, decreases with time as given by the
function F(t) =300 – 50 log5(4t + 1), where t is measured in years. How much space is left when t =
6?
Evaluate the function for the given value.
Determine whether the function is a polynomial function, a rational function, a radical function, or an exponential
function.
Provide an appropriate response.
Write the expression as the sum or difference of logarithms: log5(25x)
Determine whether the function is a polynomial function, a rational function, a radical function, or an exponential
function.
Write the logarithmic equation in its equivalent exponential form.
Write the expression as the sum or difference of logarithms.
Solve . Round the answer to three decimal places.
Write the exponential equation in its equivalent logarithmic form.
Evaluate the function for the given value.
Provide an appropriate response.
Write the expression as a single logarithm: (logmm–logmn) +4logmk
Write the expression as a single logarithm.
1
3[logw (x2–16) –logw (x –4)]
Suppose f(x) =30.2 +1.3 log(x + 1) models salinity of ocean water to depths of 1000 meters at a
certain latitude. x is the depth in meters and f(x) is the salinity in grams of salt per kilogram of
seawater (expressed as parts per thousand or ppt). Approximate the salinity, to the nearest
hundredth, when the depth is 140 meters.
In chemistry, the pH of a substance can be determined using the formula pH = –log [H+], where [
H+] represents the hydrogen ion concentration. Determine the pH of the solution which has a
hydrogen concentration of 7.0 × 10–12. Round to the nearest tenth.
The annual depreciation rate r (0 < r < 1) of a car purchased for P dollars and worth A dollars after t
years can be modeled by the following formula: log (1 – r) =1
t log A
P. Find the depreciation rate of
a car that is purchased for $30,000 and is sold 4 years later for $16,000. Express the answer as a
percent and round to the nearest whole percent.
Provide an appropriate response.
Write the expression as a single logarithm.
The number of books in a small library increases according to the function B =4800e0.05t, where t is
measured in years. How many books will the library have after 10 years?
Use a calculator to approximate the logarithm to four decimal places.
Write the expression as the sum or difference of logarithms.
(9log5 x)(2log5 y) –log54
Evaluate the function for the given value.
An economist predicts that the buying power B(x) of a dollar x years from now will be given by the
formula B(x) =0.6x. How much will today’s dollar be worth in 3 years? Round to the nearest cent.
Write the exponential equation in its equivalent logarithmic form.
The formula for the pH of a solution is given by the logarithmic equation pH = –log [H+], where [
H+] is the concentration of hydrogen ions. The concentration of hydrogen ions of a specific solution
is 10–7. Calculate the pH of this solution.
Write the expression as a single logarithm.
2logbx–2
3logby+1
6logbw– 6logbz
logb (2 x –2
3y+1
6w– 6 z )
Solve . Round the answer to three decimal places.
Use a calculator to approximate the logarithm to four decimal places.
Solve . Round the answer to three decimal places.
Write the expression as a single logarithm.
The population of a particular city is increasing at a rate proportional to its size. It follows the
function P(t) = 1 + ke0.06t where k is a constant and t is the time in years. If the current population
is 16,000, in how many years is the population expected to be 40,000? Round to the nearest year.
A certain noise has an intensity I of 5.35 ×10–4. Given that decibel level D is related to intensity by
D = 10 log I
I0, where I0 is 10–12, determine the decibel level of the noise. Round to the nearest
decibel.
Write the expression as a single logarithm.
Evaluate the function for the given value. Round to the nearest thousandth.
The height in feet of males in a certain ethnic group is approximated by H =2.6 + 2 log (0.84t)
where t is the boy’s age and 1 t
18. Use the properties of logarithms to write the expression on
the right side of the equation so that it does not contain the logarithm of a product.
H =2.6 + 2 log 0.84 + log t
H =2.6 + 2(log 0.84 – log t)
H =2.6 + 2(log 0.84 + log t)
H =2.6 + 2 log 0.84 – log t
Suppose the number of Quickie hamburgers (in millions) served yearly can be modeled by
f(x) =37.9e0.14x. Approximate how many years it takes for the number of hamburgers served to
reach 101 million. Round to the nearest year.
Write the logarithmic equation in its equivalent exponential form.
Use a calculator to approximate the logarithm to four decimal places.
The number of visitors to a tourist attraction (for the first few years after its opening) can be
approximated by V(x) = 50 + 10 log2x, where x represents the number of months after the
opening of the attraction. Find the number of visitors 32 months after the opening of the attraction.
Write the exponential equation in its equivalent logarithmic form.