+0  
 
0
53
1
avatar

\(x^2 + bx + 9\) If  has two non-real roots, find all possible values of \(b\). Express your answer in interval notation.

 

Thanks, I do not know how to solve this problem.

 Dec 9, 2018
 #1
avatar+94499 
+1

IIf we have non-real roots, the discriminant must be < 0

 

In the form

 

ax^2 + bx + c = 0

 

The discriminant is   b^2 - 4ac

 

 

So  b = b     a = 1    and c = 9       ... so.....

 

b^2 - 4 (1) (9)   < 0

 

b^2 - 36 < 0

 

b^2 < 36

 

The interval that makes this true is

 

-6 < b < 6

 

 

cool cool cool

 Dec 9, 2018

25 Online Users

avatar
avatar
avatar
avatar

New Privacy Policy

We use cookies to personalise content and advertisements and to analyse access to our website. Furthermore, our partners for online advertising receive information about your use of our website.
For more information: our cookie policy and privacy policy.