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Math III Videos 103 videos

Unit Rate
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Approximately 874 people per day wonder what a unit rate is. If you're one of them, check out our video on unit rates and how to use them. (We just...

Solving Proportions Using Cross Products
6802 Views

This video covers how to use cross products to solve for a missing number in a proportion by setting that proportion with a variable over the produ...

GED Math 2.4 Rational Numbers
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GED Math 2.4 Rational Numbers. Lucius's favorite restaurant is how many km from his home?

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Simplifying Rational Expressions 1396 Views


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Description:

Rational expressions are too complex... it's about time someone simplified them.

Language:
English Language

Transcript

00:04

Simplifying Rational Expressions, a la Shmoop.

00:07

Sam is beginning his college career, and has just joined the fraternity Alpha Delta Nerda.

00:14

School policy says that no physical hazing is allowed...

00:17

...so Alpha Delta Nerda does its own kind of hazing...

00:20

...and makes the guys solve math problems to figure out what

00:23

their "special number" will be for the rest of the year.

00:28

Sam gets an anonymous letter under his door that says,

00:31

Simplify 36 minus 3p all over 4p minus 48.

00:37

To start, let's take a look at the numerator to see if we can factor out anything.

00:41

We see that 3 is the greatest common factor of 36 and 3p,

00:45

3 goes into 36 twelve times and 3 goes into 3 one time...

00:50

...so 36 minus 3p becomes 3 times 12 minus p.

00:55

We can see that in the denominator the greatest common factor is 4.

00:59

4 goes into 4 one time and goes into 48 twelve times...

01:03

...so we can factor out the 4 to get 4 times p minus 12.

01:07

12 minus p is the same as p minus 12... when multiplied by a negative.

01:13

So we can pull out a negative 1 from the top...

01:18

to get negative 3 times p minus 12, over 4 times p minus 12.

01:27

The top and bottom of the expression have common factors of p minus 12,

01:32

so we can just cancel these out.

01:33

And we're left with negative three-fourths!

01:37

That's it! Sam's special number is negative three-fourths!

01:40

He has so got this college thing in the bag.

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