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Question

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mathmale · Answer

Have you seen in class, in your textbook or in class notes the manner in which |2x+7| > 13 could be expressed as TWO related inequalities?

anonymous · Answer

Yeaaa

mathmale · Answer

Then 2x + 7 > 13    OR -(2x + 7) > 13.  Solve for the two x values.

the_fizicx99 · Answer

2x + 7 | -3 > 10
              +3   +3

| 2x + 7 | > 13
       -7          -7

2x > 6
/2    /2

x = 3


Then make it negative to get another solution

2x + 7 | -3 > -10

You solve this one :)

mathmale · Answer

Have you checked your solutions through substitution into the original inequality?  This step is very important and should not be skipped.

I'd advise not taking short cuts until after you've gained significant experience.  Taking x = 3 and making it negative does not produce a solution in this particular problem.

Going back to my original suggestion:

Then 2x + 7 > 13    OR -(2x + 7) > 13.  Solve for the two x values.

First inequality:  This simplifies to 2x > 4, or x > 2.

Your turn.  Try solving the second inequality.

Good luck!  And remember, NO shortcuts YET!  :)