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- Dec 9th 2009, 04:29 PM #1

- Dec 9th 2009, 04:40 PM #2

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- Dec 9th 2009, 04:45 PM #3

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- Dec 9th 2009, 04:46 PM #4

- Dec 9th 2009, 04:47 PM #5
Wrong. If you multiply or divide by a negative number, it changes the direction of the inequality.

First, it is important to note that , since you can not have the square root of a negative number.

.

.

Putting it all together, we have our solution set

.

Notice that if you use any number less than 4, you need to use the NEGATIVE square root to make the sentence make sense...

- Dec 9th 2009, 04:48 PM #6

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That isn't a correct solution set.

Substitute some values back into the inequality. For example if x=1, the inequality isn't true.

-4(-1)+4=8 which isn't greater than 12.

-4(1)+4=0 which isn't greater than 12.

The answer is x>4, but how do we arrive at that?

- Dec 9th 2009, 04:48 PM #7

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- Dec 9th 2009, 05:01 PM #8

- Dec 9th 2009, 05:02 PM #9

- Dec 9th 2009, 05:16 PM #10

- Dec 9th 2009, 06:13 PM #11

- Dec 9th 2009, 06:19 PM #12

- Dec 9th 2009, 06:28 PM #13

- Dec 9th 2009, 06:42 PM #14

- Dec 9th 2009, 07:14 PM #15