Algebra II : Logarithms

Study concepts, example questions & explanations for Algebra II

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Example Questions

Example Question #11 : Solving And Graphing Logarithms

Possible Answers:

Correct answer:

Explanation:

To solve this equation, you must first simplify the log expressions and remember log laws (; ). Therefore, for the first expression, so . For the second expression, so  Then, substitute those numbers in so that you get .

Example Question #19 : Solving Logarithms

Solve for 

Possible Answers:

Correct answer:

Explanation:

 

Remember that a logarithm is nothing more than an exponent. The equation reads, the logarithm (exponent) with base  that gives  is

 

 

Example Question #20 : Solving Logarithms

Solve the equation

Possible Answers:

None of the other answers

Correct answer:

Explanation:

Since both sides are a log with the same base, their arguments must be equal.

Setting them equal:

Solve for x:

Example Question #21 : Solving Logarithms

Solve the equation

Possible Answers:

No Solution

Correct answer:

No Solution

Explanation:

Set the arguments of the natural log equal and solve for 

However, you cannot take the natural log of a negative number. Therefore; there is No Solution

Example Question #22 : Solving Logarithms

Solve:

Possible Answers:

Correct answer:

Explanation:

To solve this problem, it is easiest to start by thinking about what the logarithm means:

Now, we take the log of both sides (either base-10 or natural):

Next, using the properties of logarithms, we can bring the exponent x in front of the logarithm:

Finally, solve for x:

Example Question #23 : Solving Logarithms

Evaluate

Possible Answers:

Correct answer:

Explanation:

Logarithms are inverses of exponents. 

 is asking how many fives multiplied together are equal to 25.

The formula to solve logarithmic equations is as follows.

Applying this formula to our particular problem results in the following.

 

 = 

So .

Example Question #161 : Logarithms

Solve:

Possible Answers:

Correct answer:

Explanation:

To solve, we must keep in mind that a logarithm is asking the following:

means , and we must find x.

First, we can rewrite the sum of the base-8 logarithms as a product (this is a property of logarithms):

Now, we use the above formula to find what this numerically equals:

Take the natural or common logarithm of both sides, which allows us to bring the power x in front of the logarithm:

Example Question #25 : Solving Logarithms

Solve for x:

Possible Answers:

Correct answer:

Explanation:

To solve for x, we must take the logarithm of both sides (common or natural, it doesn't matter):

In doing this, we can now bring the exponents in front of the logarithms:

Now, solve for x:

Example Question #161 : Logarithms

If  and , what is ?

Possible Answers:

Correct answer:

Explanation:

First, we know from logarithmic properties that:

So if we can find a combination of our knowns that equal , we should be able to figure out .  It may take some guess and check, but:

That would equate to:

Using our log properties, we can simplify into:

That means that:

 

Example Question #27 : Solving Logarithms

Evaluate .

Possible Answers:

Correct answer:

Explanation:

There are a few ways to go about this, but let's use a change of base to make the problem easier to work without using a calculator.  First, we know that:

We can choose any value for  that we would like here, so to make things simple, let's put this problem in base :

 

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