Algebra II : Logarithms

Study concepts, example questions & explanations for Algebra II

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Example Questions

Example Question #42 : Adding And Subtracting Logarithms

Simplify .

Possible Answers:

Correct answer:

Explanation:

First we can make the coefficient from the left term into an exponent:

Next, remember that if we're subtracting logs, we divide the terms inside them:

Example Question #41 : Adding And Subtracting Logarithms

Simplify 

Possible Answers:

Correct answer:

Explanation:

When we add logs, we multiply the terms in them:

From here, we multiply them out:

Example Question #54 : Simplifying Logarithms

True or false: for all positive values of 

Possible Answers:

True

False

Correct answer:

True

Explanation:

By the Product of Logarithms Property, 

Setting , this becomes 

"log" refers to the common, or base ten, logarithm, so, by definition,

if and only if

.

Setting 

,

so 

and .

The statement is true.

Example Question #55 : Simplifying Logarithms

True or false:  for all values of .

Possible Answers:

False

True

Correct answer:

False

Explanation:

A statement can be proved to not be true in general if one counterexample can be found. One such counterexample assumes that . The statement 

becomes 

or, equivalently,

The word "log" indicates a common, or base ten, logarithm, as opposed to a natural, or base , logarithm. By definition, the above statement is true if and only if

or

.

This is false, so  does not hold for . Since the statement fails for one value, it fails in general.

Example Question #42 : Adding And Subtracting Logarithms

True or false:

for all negative values of .

Possible Answers:

False

True

Correct answer:

False

Explanation:

It is true that by the Product of Logarithms Property, 

.

However, this only holds true if both  and  are positive. The logarithm of a negative number is undefined, so the expression  is undefined. The statement is therefore false.

Example Question #43 : Adding And Subtracting Logarithms

True or false:  for all positive .

Possible Answers:

False

True

Correct answer:

True

Explanation:

By the Change of Base Property of Logarithms, if  and 

Substituting 7 for  and 6 for , the statement becomes the given statement 

.

The correct choice is "true."

Example Question #121 : Logarithms

In this question we will use the notation  to represent the base 10 or common logarithm, i.e. .

Find  if .

Possible Answers:

Correct answer:

Explanation:

We can use the Property of Equality for Logarithmic Functions to take the logarithm of both sides:

Use the Power Property of Logarithms:

Divide each side by  :

Use a calculator to get:

   

or

Example Question #122 : Logarithms

Simplify 

Possible Answers:

Correct answer:

Explanation:

Using Rules of Logarithm recall: 

 

Thus, in this situation we bring the 2 in front and we get our solution. 

Example Question #125 : Logarithms

Simplify the following equation.

Possible Answers:

Correct answer:

Explanation:

We can simplify the natural log exponents by using the following rules for naturla log.

Using these rules, we can perform the following steps.

Knowing that the e cancels the exponential natural log, we can cancel the first e.

Distribute the square into the parentheses and calculate.

Remember that a negative exponent is equivalent to a quotient. Write it as a quotient and then you're finished.

Example Question #1 : Logarithms With Exponents

Evaluate the following expression

Possible Answers:

Correct answer:

Explanation:

Since the exponent is inside the parentheses, you must take the square of 1000 before finding the logarithim.  Therefore

because 

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