SOLUTION: solve (x+20)(x-9)(x+6)>0 A).The solution set is {x|___}? B).The solution to all real numbers C).There are no solutions

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: solve (x+20)(x-9)(x+6)>0 A).The solution set is {x|___}? B).The solution to all real numbers C).There are no solutions      Log On


   

Question 338678: solve (x+20)(x-9)(x+6)>0
A).The solution set is {x|___}?
B).The solution to all real numbers
C).There are no solutions
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
%28x%2B20%29%28x-9%29%28x%2B6%29%3E0
Break up the number line into 4 regions.
Region 1: (-infinity,-20)
Region 2: (-20,-6)
Region 3: (-6,9)
Region 4: (9,infinity)
Choose a point in each region (not an endpoint).
Test the inequality.
If the inequality is satisfied, the region is part of the solution region.
.
.
.
Region 1: x=-21
%28x%2B20%29%28x-9%29%28x%2B6%29%3E0
%28-21%2B20%29%28-21-9%29%28-21%2B6%29%3E0
%28-1%29%28-30%29%28-15%29%3E0
False, this region is not part of the solution.
.
.
.
Region 2: x=-10
%28x%2B20%29%28x-9%29%28x%2B6%29%3E0
%28-10%2B20%29%28-10-9%29%28-10%2B6%29%3E0
%2810%29%28-19%29%28-4%29%3E0
True, this region is part of the solution.
.
.
.
Region 3: x=0
%28x%2B20%29%28x-9%29%28x%2B6%29%3E0
%2820%29%28-9%29%286%29%3E0
False, this region is not part of the solution.
.
.
.
Region 4: x=10
%28x%2B20%29%28x-9%29%28x%2B6%29%3E0
%2810%2B20%29%2810-9%29%2810%2B6%29%3E0
%2830%29%281%29%2816%29%3E0
Ture, this region is part of the solution.
.
.
.
Solution:(-20,-6) U (9,infinity)