SOLUTION: |2x-9|<11

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Question 255117: |2x-9|<11
Found 2 solutions by stanbon, Edwin McCravy:
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
|2x-9|<11
-11 < 2x-9 < 11
Add 9 along the line to get:
-2 < 2x < 20
Divide by 2 along the line to get:
-1 < x < 10
======================
Cheers,
Stan H.

Answer by Edwin McCravy(20086) About Me  (Show Source):
You can put this solution on YOUR website!

abs%282x-9%29%3C11

Learn the ways to rewrite absolute value inequalities
without using absolute value bars:

"EXPRESSION" refers to whatever is between the absolute value bars.
"N" refers to whatever POSITIVE* number is on the right side.

1. abs%28EXPRESSION%29%3CN can be rewritten without absolute value bars as -N%3CEXPRESSION%3CN

2. abs%28EXPRESSION%29%3C=N can be rewritten without absolute value bars as -N%3C=EXPRESSION%3C=N

3. abs%28EXPRESSION%29%3EN can be rewritten without absolute value bars as EXPRESSION%3C-NOREXPRESSION%3EN, 
and the word "OR" must be included.

4, abs%28EXPRESSION%29%3E=N can be rewritten without absolute value bars as EXPRESSION%3C=-NOREXPRESSION%3E=N,
and the word "OR" must be included.

Yours is case 1 but I thought I'd include the others so you could
solve other inequalities you'll be studying.

The "EXPRESSION" here is is what's between the absolute value bars,
and that is "2x-9" and "N" is 11. 

abs%282x-9%29%3C11 can be rewritten without absolute value bars as -11%3C2x-9%3C11

You solve 

     -11 < 2x - 9 < 11

by getting x alone in the MIDDLE.  Begin by adding 9 to all
three sides:

     -11 < 2x - 9 < 11
      +9       +9   +9
     -----------------
      -2 < 2x     < 20

Then divide all three sides by 2 and
since 2 is not a negative number the
inequalities are not reversed.

     %28-2%29%2F2+%3C+%282x%29%2F2+%3C+20%2F2
     -1%3Cx%3C10

The graph of that solution is

---------o===========================================o--------
-3  -2  -1   0   1   2   3   4   5   6   7   8   9  10  11  12 

and the interval notation for that is (-1, 10)

Edwin

* when N is not a positive number, there is no solution in
cases 1 and 2, and "all real numbers" in cases 3 and 4.