+0  
 
0
248
6
avatar

For what value of the constant k\(\) does the quadratic \( 2x^2 - 5x + k\) have a double root?

Guest Dec 27, 2017
edited by Guest  Dec 27, 2017

Best Answer 

 #3
avatar+2190 
+2

Rahuan, I am not completely sure what it means either, but I will interpret "double root" as a zero with a multiplicity of two. Assuming the above is true, we can use the property of the discriminant of a quadratic, \(b^2-4ac\) . The discriminant, if equal to zero, results in a quadratic with a "double root." 

 

\(b^2-4ac=0\) Plug in the given values of a, b, and c of the quadratic. 
\((-5)^2-4(2)(k)=0\) Now, solve for k. 
\(25-8k=0\) Subtract 25 from both sides. 
\(-8k=-25\)  
\(k=\frac{25}{8} \)  
   
   
   
   
   
   
   
   
   
   
TheXSquaredFactor  Dec 27, 2017
 #1
avatar+502 
0

I understood until the equation part but what do u mean by double root?

Rauhan  Dec 27, 2017
 #2
avatar+502 
0

or do u mean square root/ just (x2). (x = any number/ coefficients etc)

Rauhan  Dec 27, 2017
 #5
avatar
0

a repeated root

Guest Dec 27, 2017
 #3
avatar+2190 
+2
Best Answer

Rahuan, I am not completely sure what it means either, but I will interpret "double root" as a zero with a multiplicity of two. Assuming the above is true, we can use the property of the discriminant of a quadratic, \(b^2-4ac\) . The discriminant, if equal to zero, results in a quadratic with a "double root." 

 

\(b^2-4ac=0\) Plug in the given values of a, b, and c of the quadratic. 
\((-5)^2-4(2)(k)=0\) Now, solve for k. 
\(25-8k=0\) Subtract 25 from both sides. 
\(-8k=-25\)  
\(k=\frac{25}{8} \)  
   
   
   
   
   
   
   
   
   
   
TheXSquaredFactor  Dec 27, 2017
 #4
avatar+502 
0

does he mean like finding the value of k and then putting the answer as \(\frac{5^2}{8}\)

Rauhan  Dec 27, 2017
 #6
avatar+2190 
0

I do not believe so; there is no reason not to simplify the fraction completely. 

TheXSquaredFactor  Dec 28, 2017

17 Online Users

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.