Destroyer 2011 Math #101

[BMEEngineer]

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This is an inequality problem:

http://imgur.com/kMJDMNT

The answer is greater than equal to 13
and less than equal to -7

In one of the answers, they flip the sign when multiplying both sides by 2 (and the other side in -5).

My understanding is that whenever you are multiplying or dividing both sides by a negative number, that is when the inequality gets flipped. What am I missing here?

Thank you!

 

[Centry]

To solve this, make x-3/2 greater than or equal to 5. Also, make x-3/2 less than or equal to -5. Set those two equations up separately, and solve for the answers. Use this method to solve all absolute value - inequality questions.

 

[BMEEngineer]

To solve this, make x-3/2 greater than or equal to 5. Also, make x-3/2 less than or equal to -5. Set those two equations up separately, and solve for the answers. Use this method to solve all absolute value - inequality questions.

So when using this method, do you always automatically flip the sign for the negative number when you write the two equations out?

 

[Centry]

So when using this method, do you always automatically flip the sign for the negative number when you write the two equations out?

Yeah.

The two equations you want to solve are: 1) the regular equation, with the absolute value bars removed. 2) flip the sign, and multiply the number on the right by -1