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Basic Operations Videos 58 videos

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SAT Math 7.3 Algebra and Functions
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SAT Math 7.3 Algebra and Functions

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CAHSEE Math 3.2 Algebra and Functions 193 Views


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Description:

Algebra and Functions: Drill Set 3, Problem 2. Simplify the expression in this video.

Language:
English Language

Transcript

00:03

And here's your shmoop du jour.

00:05

Simplify the expression 2a to the fourth times 4a to the negative second.

00:10

Here are the potential answers...

00:12

Before we spoil the ending, hit pause and try it yourself.

00:18

Remember order of operations, or PEMDAS?

00:21

Please excuse my dear aunt sally... or parentheses, exponents, multiplication/division, and addition/subtraction.

00:27

PEMDAS tells us to work with the variables inside the parentheses first.

00:31

2a and 4a can't get any simpler...

00:33

...so we can move to the exponents.

00:35

We have the quantity 2a to the 4th, which means that we take 2 to the 4th...

00:40

...which is 16 times a to the 4th, so... 16a to the 4th.

00:46

Next we have the quantity 4a to the negative second.

00:49

Don't forget that little negative next to the 2 in the exponent.

00:53

Remember that negative exponents basically just mean "1 over."

00:57

We can move the 4a into the denominator and square it...which simplifies the fraction

01:02

as 1 over 16 times a squared.

01:05

When we multiply 16a to the 4th and one over 16 a-squared, we can cancel out the 16

01:10

over 16 to 1 over 1... or 1.

01:14

...and cancel the a to the 4th over a squared to a squared.

01:19

This leaves us with a squared... or the answer... which also happens to be A.

01:23

Now let's get out of here before Aunt Sally sets this whole place on fire.

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