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Algebra II Videos 54 videos

SAT Math 4.1 Algebra and Functions
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SAT Math 4.1 Algebra and Functions

SAT Math 5.4 Algebra and Functions
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SAT Math 5.4 Algebra and Functions

SAT Math 8.5 Algebra and Functions
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SAT Math 8.5 Algebra and Functions

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Multiplying Rational Expressions 2529 Views


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Description:

Multiplying rational expressions is as easy as adding the exponents and simplifying. Ta da!

Language:
English Language

Transcript

00:04

Multiplying Rational Expressions, a la Shmoop.

00:08

In the distant future, arguments between friends and roommates will be solved with math.

00:13

Today, we'll see how it might be used to solve a problem between two roommates on a space

00:17

station orbiting Jupiter.

00:19

Meet Xavier and Yumi.

00:27

Their dilemma is represented by the following...

00:30

4 x over 5 y squared times 20 x-squared y over y to the fourth.

00:36

Now let's talk about what they have in common.

00:39

Remember, usually when we multiply fractions, we multiply across top and bottom.

00:44

But when we see a chance, we can simplify first by canceling any duplicate factors.

00:49

Looking at our problem, we can see that the 20 in the top of the second fraction

00:53

and the 5 in the bottom of the first fraction are both factors of 5.

00:58

We can simplify by dividing 20 by 5 to get 4,

01:02

and divide the 5 on the bottom by 5 to get 1.

01:06

Looking at the second fraction, we can cancel the top y with the y to the fourth on the bottom...

01:13

leaving y to the power of three.

01:15

Now we can just multiply across the top of the two fractions...

01:18

4 x times 4 x-squared equals 16 x-cubed.

01:24

And multiply across the bottom... y-squared times y-cubed...

01:28

...remember that we multiply two terms with the same base, and we can add the two exponents...

01:34

in this case, the 2 and 3, to get y to the fifth.

01:38

So the answer is 16 x cubed over y to the power of 5.

01:42

And on the space station orbiting Jupiter, this result means that it's Xavier's turn

01:46

to take out the plutonium.

01:49

Don't forget to shut the airlock.

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