Algebra II : Algebra II

Study concepts, example questions & explanations for Algebra II

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Example Questions

Example Question #207 : Logarithms

Solve .

Possible Answers:

Correct answer:

Explanation:

The first thing we can do is get rid of the exponent in the second log, and then divide both sides by that coefficient:

It can be a pain to work with logs of different bases, so let's change the base  log to base :

We can now take the denominator, expand, and simplify:

Now, we combine the log terms:

Taking the square root of each side:

We have to solve for both the plus, and the minus.  Let's start with the negative:

And now the positive:

Plugging both of these answers into the original equation produces no errors, so both answers are valid.

Example Question #208 : Logarithms

Solve .

Possible Answers:

Correct answer:

Explanation:

First, we can use the log product rule to combine the log terms:

Now we write the equation in exponential form:

If we plug  into the original equation, we get errors (we can't take the log of a negative value).   is fine though, and is our only solution.

Example Question #61 : Solving And Graphing Logarithms

Solve .

Possible Answers:

Correct answer:

Explanation:

We can combine the logs on the right side of the equation while also using the product rule on the log on the left side:

Since the logs have the same base, we can equate the algebraic equations equal to each other:

Now we can solve the quadratic equation:

Plugging this into the original equation doesn't produce errors, so it's our single solution.

Example Question #210 : Logarithms

Solve .

Possible Answers:

Correct answer:

Explanation:

First we take the natural log of both sides of the equation:

Remember, taking the natural log of  with an exponent equals that exponent, and the natural log of  is :

Form here, we solve algebraically:

Example Question #211 : Logarithms

Solve .

Possible Answers:

Correct answer:

Explanation:

First we start by subtracting  from each side:

Next, we rewrite the equation in exponent form:

Finally, we divide by :

Example Question #212 : Logarithms

Solve .

Possible Answers:

Correct answer:

Explanation:

First, we subtract  from each side:

Next, we divide each side by :

Now we rewrite the equation in exponent form:

And we finish using algebra:

Example Question #213 : Logarithms

Solve 

Possible Answers:

Correct answer:

Explanation:

First, we add  to each side:

Next, we take the exponent in the log and make it a coefficient:

And divide by the new coefficient:

Now we write the equation in exponent form:

Example Question #71 : Solving And Graphing Logarithms

Solve .

Possible Answers:

Correct answer:

Explanation:

The first thing we can do is combine all the log terms on the right side of the equation:

Next, we can take the coefficient from the left term and make it an exponent:

Now we can cancel the logs from both sides:

When we put  back into the original question, we don't have problems.  When we try it with  however, we get errors, so that's not a valid answer:

Example Question #72 : Solving Logarithms

Solve .

Possible Answers:

Correct answer:

Explanation:

First, we take the coefficient, , and make it an exponent:

Now we can cancel the logs:

When we check our answers, however, we notice that  results in errors, so that's not a valid answer:

Example Question #211 : Logarithms

Solve ,

Possible Answers:

Correct answer:

Explanation:

First, we combine the log terms on the left of the equation:

Now we can cancel the logs on each side:

We can subtract  from each side to set the equation equal to .  this will give us a nice quadratic equation to solve:

Notice that  is not a valid answer, because if we plug it into the original equation then we would be taking the log of a negative number, which we can't do.  Our only solution is:

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