Algebra II : Multiplying and Dividing Rational Expressions

Study concepts, example questions & explanations for Algebra II

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Example Questions

Example Question #11 : Multiplying And Dividing Rational Expressions

Simplify:

 

Possible Answers:

Correct answer:

Explanation:

The numerator is equivalent to

 

The denominator is equivalent to

 

 

Dividing the numerator by the denominator, one gets

Example Question #11 : Multiplying And Dividing Rational Expressions

(9x2 – 1) / (3x – 1) = 

Possible Answers:

3

3x

(3x – 1)2

3x – 1

3x + 1

Correct answer:

3x + 1

Explanation:

It's much easier to use factoring and canceling than it is to use long division for this problem. 9x2 – 1 is a difference of squares. The difference of squares formula is a2 – b2 = (a + b)(a – b). So 9x2 – 1 = (3x + 1)(3x – 1). Putting the numerator and denominator together, (9x2 – 1) / (3x – 1) = (3x + 1)(3x – 1) / (3x – 1) = 3x + 1.

Example Question #102 : Rational Expressions

Simplify:

 

 

Possible Answers:

None of the above

Correct answer:

Explanation:

Factor both the numerator and the denominator which gives us the following:

After cancelling we get

 

Example Question #11 : Multiplying And Dividing Rational Expressions

Simplify:  

Possible Answers:

Correct answer:

Explanation:

There is a common factor in the numerator.   Pull out the common factor and rewrite the numerator.

Factorize the denominator.

Cancel the  term in the numerator and denominator.

The answer is: 

Example Question #12 : Multiplying And Dividing Rational Expressions

Multiply:

Possible Answers:

Correct answer:

Explanation:

First factor the numerators and denominators of the two fractions. This allows us to re-write the original problem like this:

Now we can cancel terms that appear on both the top and the bottom, since they will divide to be a factor of . This means we can can cancel the top and bottom, the top and bottom , and the top and bottom . This leaves us with the following answer:

 

Example Question #13 : Multiplying And Dividing Rational Expressions

Possible Answers:

Correct answer:

Explanation:

First, completely factor all 4 quadratics:

Now we can cancel all factors that appear on both the top and the bottom, because those will divide to a factor of . We quickly realize that all of the factors can be crossed off. This means that all of the factors have been divided to . This leves us with the following answer:

Example Question #14 : Multiplying And Dividing Rational Expressions

Multiply:

Possible Answers:

Correct answer:

Explanation:

First, completely factor everything that can possibly be factored. This includes both numerators and the second denominator:

Now we can cancel everything that appears both on the top and the bottom, since it will divide to be a factor of :

We can simplify this by multiplying  and .

This leaves us with the following answer:

Example Question #12 : Multiplying And Dividing Rational Expressions

Possible Answers:

Correct answer:

Explanation:

I would first start by simplifying the numerator by getting rid of the negative exponents: . Then, combine the denominator fractions into one fraction: . At this point, we're dividing fractions so we have to multiply by the reciprocal of the second fraction: . Multiply straight across to get: . Make sure it can't be simplified (it can't)!

Example Question #16 : Multiplying And Dividing Rational Expressions

Possible Answers:

Correct answer:

Explanation:

First, combine the top two fractions. The common denominator between the two is Therefore, you just have to offset the first fraction so that it becomes . Then, combine the numerators to get . So at this point, we have: . This is essentially a dividing fractions problem. When we divide fractions, we have to make the second fraction its reciprocal (flip it!) and then multiply the two. . The 's cross out so your final answer is: .

Example Question #17 : Multiplying And Dividing Rational Expressions

Find the quotient of these rational expressions: 

Possible Answers:

None of the other answers.

Correct answer:

Explanation:

When you divide by a fraction you must multiply by its reciprocal to get the correct quotient.

Factor where able:

Cancel like terms:

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