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Hello, I have been stuck with this problem:

What is the value of b+c if x^2+bx+c>0 only when x is (-inf, -2) U (3, inf)

I'm not entirely sure on how to solve this problem, a little push in the right direction would be helpful,

 

Thanks in advance!

 Apr 12, 2021

Best Answer 

 #1
avatar+33727 
+1

Basically this is a parbola with the zeroes at -2   and 3    .......it is negative in between these two points (less than zero)

 

(x+2)(x-3) = x^2 -x - 6 

   (you can calc b+c from here)

here is the graph:

 

https://www.desmos.com/calculator/yofniiyxqn

 Apr 12, 2021
edited by ElectricPavlov  Apr 12, 2021
 #1
avatar+33727 
+1
Best Answer

Basically this is a parbola with the zeroes at -2   and 3    .......it is negative in between these two points (less than zero)

 

(x+2)(x-3) = x^2 -x - 6 

   (you can calc b+c from here)

here is the graph:

 

https://www.desmos.com/calculator/yofniiyxqn

ElectricPavlov Apr 12, 2021
edited by ElectricPavlov  Apr 12, 2021
 #2
avatar
0

Thank you for your help! I got my answer now :)

Guest Apr 13, 2021

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