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# Please Help with Quadratic Inequalites

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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
+31573
+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

### 2+0 Answers

#1
+31573
+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
0

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

Guest Apr 13, 2021