Chapter 4

College Algebra Essentials · 476 exercises

Problem 14

Use properties of logarithms to expand logarithmic expression as much as possible. Where possible, evaluate logarithmic expressions without using a calculator. \(\ln \left(\frac{e^{4}}{8}\right)\)

3 step solution

Problem 15

An artifact originally had 16 grams of carbon- 14 present. The decay model \(A=16 e^{-0.0001211}\) describes the amount of carbon-I4 present after t years. Use this model to solve Exercises \(15-16 .\) How many grams of carbon-14 will be present in 5715 years?

3 step solution

Problem 15

Solve each exponential equation by expressing each side as a power of the same base and then equating exponents. $$6^{\frac{x-3}{4}}=\sqrt{6}$$

3 step solution

Problem 15

Write each equation in its equivalent logarithmic form. $$13^{2}=x$$

2 step solution

Problem 15

Graph each function by making a table of coordinates. If applicable, use a graphing utility to confirm your hand-drawn graph. $$h(x)=\left(\frac{1}{2}\right)^{x}$$

3 step solution

Problem 15

Use properties of logarithms to expand logarithmic expression as much as possible. Where possible, evaluate logarithmic expressions without using a calculator. \(\log _{b} x^{3}\)

6 step solution

Problem 16

An artifact originally had 16 grams of carbon- 14 present. The decay model \(A=16 e^{-0.0001211}\) describes the amount of carbon-I4 present after t years. Use this model to solve Exercises \(15-16 .\) How many grams of carbon-14 will be present in \(11,430\) years?

4 step solution

Problem 16

Solve each exponential equation by expressing each side as a power of the same base and then equating exponents. $$7^{\frac{x-2}{6}}=\sqrt{7}$$

3 step solution

Problem 16

Write each equation in its equivalent logarithmic form. $$15^{2}=x$$

2 step solution

Problem 16

Graph each function by making a table of coordinates. If applicable, use a graphing utility to confirm your hand-drawn graph. $$h(x)=\left(\frac{1}{3}\right)^{x}$$

4 step solution

Problem 16

Use properties of logarithms to expand logarithmic expression as much as possible. Where possible, evaluate logarithmic expressions without using a calculator. \(\log _{b} x^{7}\)

2 step solution

Problem 17

The half-life of the radioactive element krypton-91 is 10 seconds. If 16 grams of krypton-91 are initially present, how many grams are present after 10 seconds? 20 seconds? 30 seconds? 40 seconds? 50 seconds?

3 step solution

Problem 17

Solve each exponential equation by expressing each side as a power of the same base and then equating exponents. $$4^{x}=\frac{1}{\sqrt{2}}$$

3 step solution

Problem 17

Write each equation in its equivalent logarithmic form. $$b^{3}=1000$$

2 step solution

Problem 17

Graph each function by making a table of coordinates. If applicable, use a graphing utility to confirm your hand-drawn graph. $$f(x)=(0.6)^{x}$$

3 step solution

Problem 17

Use properties of logarithms to expand logarithmic expression as much as possible. Where possible, evaluate logarithmic expressions without using a calculator. \(\log N^{-6}\)

2 step solution

Problem 18

The half-life of the radioactive element plutonium-239 is \(25,000\) years. If 16 grams of plutonium- 239 are initially present, how many grams are present after \(25,000\) years? \(50,000\) years? \(75,000\) years? \(100,000\) years? \(125,000\) years?

6 step solution

Problem 18

Solve each exponential equation by expressing each side as a power of the same base and then equating exponents. $$9^{x}=\frac{1}{\sqrt[3]{3}}$$

3 step solution

Problem 18

Write each equation in its equivalent logarithmic form. $$b^{3}=343$$

2 step solution

Problem 18

Graph each function by making a table of coordinates. If applicable, use a graphing utility to confirm your hand-drawn graph. $$f(x)=(0.8)^{x}$$

3 step solution

Problem 18

Use properties of logarithms to expand logarithmic expression as much as possible. Where possible, evaluate logarithmic expressions without using a calculator. \(\log M^{-8}\)

3 step solution

Problem 19

Solve each exponential equation by expressing each side as a power of the same base and then equating exponents. $$8^{x+3}=16^{x-1}$$

4 step solution

Problem 19

Write each equation in its equivalent logarithmic form. $$7^{y}=200$$

4 step solution

Problem 19

Use properties of logarithms to expand logarithmic expression as much as possible. Where possible, evaluate logarithmic expressions without using a calculator. \(\ln \sqrt[5]{x}\)

4 step solution

Problem 20

Use the exponential decay model for carbon- \(14, A=A_{0} e^{-0.000121 t}\) to solve Exercises \(19-20\) Skeletons were found at a construction site in San Francisco in \(1989 .\) The skeletons contained \(88 \%\) of the expected amount of carbon-14 found in a living person. In \(1989,\) how old were the skeletons?

4 step solution

Problem 20

Solve each exponential equation by expressing each side as a power of the same base and then equating exponents. $$8^{1-x}=4^{x+2}$$

3 step solution

Problem 20

Write each equation in its equivalent logarithmic form. $$8^{y}=300$$

2 step solution

Problem 20

Use properties of logarithms to expand logarithmic expression as much as possible. Where possible, evaluate logarithmic expressions without using a calculator. \(\ln \sqrt[7]{x}\)

3 step solution

Problem 21

Solve each exponential equation by expressing each side as a power of the same base and then equating exponents. $$e^{x+1}=\frac{1}{e}$$

3 step solution

Problem 21

Evaluate each expression without using a calculator. $$\log _{4} 16$$

3 step solution

Problem 21

Use properties of logarithms to expand logarithmic expression as much as possible. Where possible, evaluate logarithmic expressions without using a calculator. \(\log _{b}\left(x^{2} y\right)\)

3 step solution

Problem 22

Solve each exponential equation by expressing each side as a power of the same base and then equating exponents. $$e^{x+4}=\frac{1}{e^{2 x}}$$

3 step solution

Problem 22

Evaluate each expression without using a calculator. $$\log _{7} 49$$

2 step solution

Problem 22

Use properties of logarithms to expand logarithmic expression as much as possible. Where possible, evaluate logarithmic expressions without using a calculator. \(\log _{b}\left(x y^{3}\right)\)

3 step solution

Problem 23

Solve each exponential equation. Express the solution set in terms of natural logarithms or common logarithms. Then use a calculator to obtain a decimal approximation, correct to two decimal places, for the solution. $$10^{x}=3.91$$

3 step solution

Problem 23

Evaluate each expression without using a calculator. $$\log _{2} 64$$

3 step solution

Problem 23

Use properties of logarithms to expand logarithmic expression as much as possible. Where possible, evaluate logarithmic expressions without using a calculator. \(\log _{4}\left(\frac{\sqrt{x}}{64}\right)\)

4 step solution

Problem 24

Solve each exponential equation. Express the solution set in terms of natural logarithms or common logarithms. Then use a calculator to obtain a decimal approximation, correct to two decimal places, for the solution. $$10^{x}=8.07$$

3 step solution

Problem 24

Evaluate each expression without using a calculator. $$\log _{3} 27$$

3 step solution

Problem 24

Use properties of logarithms to expand logarithmic expression as much as possible. Where possible, evaluate logarithmic expressions without using a calculator. \(\log _{5}\left(\frac{\sqrt{x}}{25}\right)\)

4 step solution

Problem 25

Solve each exponential equation. Express the solution set in terms of natural logarithms or common logarithms. Then use a calculator to obtain a decimal approximation, correct to two decimal places, for the solution. $$e^{x}=5.7$$

3 step solution

Problem 25

Begin by graphing \(f(x)=2^{x}\). Then use transformations of this graph to graph the given function. Be sure to graph and give equations of the asymptotes. Use the graphs to determine each function's domain and range. If applicable, use a graphing utility to confirm your hand-drawn graphs. $$g(x)=2^{x+1}$$

5 step solution

Problem 25

Evaluate each expression without using a calculator. $$\log _{5} \frac{1}{5}$$

3 step solution

Problem 25

Use properties of logarithms to expand logarithmic expression as much as possible. Where possible, evaluate logarithmic expressions without using a calculator. \(\log _{6}\left(\frac{36}{\sqrt{x+1}}\right)\)

5 step solution

Problem 26

Solve each exponential equation. Express the solution set in terms of natural logarithms or common logarithms. Then use a calculator to obtain a decimal approximation, correct to two decimal places, for the solution. $$e^{x}=0.83$$

2 step solution

Problem 26

Begin by graphing \(f(x)=2^{x}\). Then use transformations of this graph to graph the given function. Be sure to graph and give equations of the asymptotes. Use the graphs to determine each function's domain and range. If applicable, use a graphing utility to confirm your hand-drawn graphs. $$g(x)=2^{x+2}$$

4 step solution

Problem 26

Evaluate each expression without using a calculator. $$\log _{6} \frac{1}{6}$$

3 step solution

Problem 26

Use properties of logarithms to expand logarithmic expression as much as possible. Where possible, evaluate logarithmic expressions without using a calculator. \(\log _{8}\left(\frac{64}{\sqrt{x+1}}\right)\)

4 step solution

Problem 27

Solve each exponential equation. Express the solution set in terms of natural logarithms or common logarithms. Then use a calculator to obtain a decimal approximation, correct to two decimal places, for the solution. $$5^{x}=17$$

3 step solution

Problem 27

Begin by graphing \(f(x)=2^{x}\). Then use transformations of this graph to graph the given function. Be sure to graph and give equations of the asymptotes. Use the graphs to determine each function's domain and range. If applicable, use a graphing utility to confirm your hand-drawn graphs. $$g(x)=2^{x}-1$$

4 step solution

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