Exponents/447471 (2011-05-10 08:40:47): Solve the absolute value inequality. Write the solution set using interval notation
|b + 4| - 7 > 11
Get the absolute value term by itself by adding 7 to both sides:
|b + 4| > 18
There are four rules for removing absolute value bars in
absolute value inequalities:
If A is positive:
1. |EXPRESSION| < A becomes
-A < EXPRESSION < A
2. |EXPRESSION| ≦ A becomes
-A ≦ EXPRESSION ≦ A
3. |EXPRESSION| > A becomes
EXPRESSION < -A OR EXPRESSION > A
4. |EXPRESSION| ≧ A becomes
EXPRESSION ≦ -A OR EXPRESSION ≧ A
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|b + 4| > 18
is rule 3 above where EXPRESSION = b + 4 and A = 4
|b + 4| > 18 becomes
b + 4 < -18 OR b + 4 > 18
Solve each for b:
b < -22 OR b > 14
Draw the graph on a number line:
<==============o-----------------------o===============>
-22 14
Then the interval notation for this is an abbreviation
for this graph
(-∞,-22) U (14,∞)
Edwin