SOLUTION: Solve {{{ (x+18)(x-3)(x+13)>0 }}} 1) The solution set is???? "use at least one inequality or compund inequality to express your answer" Please help me

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: Solve {{{ (x+18)(x-3)(x+13)>0 }}} 1) The solution set is???? "use at least one inequality or compund inequality to express your answer" Please help me      Log On


   

Question 359025: Solve
+%28x%2B18%29%28x-3%29%28x%2B13%29%3E0+

1) The solution set is????
"use at least one inequality or compund inequality to express your answer"

Please help me
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
+%28x%2B18%29%28x-3%29%28x%2B13%29%3E0+
Break up the number line into 4 regions using the critical points of the function.
Region 1:(-infinity,-18)
Region 2:(-18,-13)
Region 3:(-13,3)
Region 4:(3,infinity)
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For each region, choose a point in the region (not an endpoint).
Test the inequality.
If the inequality is satisfied, the region is part of the solution region.
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Region 1:x=-19
+%28x%2B18%29%28x-3%29%28x%2B13%29%3E0+
+%28-19%2B18%29%28-19-3%29%28-19%2B13%29%3E0+
%28-1%29%28-22%29%28-6%29%3E0+
-132%3E0+
False, Region 1 is not part of the solution region.
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Region 2:x=-14
+%28x%2B18%29%28x-3%29%28x%2B13%29%3E0+
+%28-14%2B18%29%28-14-3%29%28-14%2B13%29%3E0+
%284%29%28-17%29%28-1%29%3E0+
68%3E0+
True, Region 2 is part of the solution region.
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Region 3:x=0
+%28x%2B18%29%28x-3%29%28x%2B13%29%3E0+
%2818%29%28-3%29%2813%29%3E0+
-702%3E0+
False, Region 3 is not part of the solution region.
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Region 4:x=4
+%28x%2B18%29%28x-3%29%28x%2B13%29%3E0+
+%284%2B18%29%284-3%29%284%2B13%29%3E0+
%2822%29%281%29%2817%29%3E0+
374%3E0+
True, Region 4 is part of the solution region.
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Solution Region: (-18,-13) U (3,infinity)
or
(-18%3Cx%3C-13) and (x%3E3)
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Graphical verification: Look for regions where the function is above the x-axis (y%3E0)
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