We use cookies to personalise content and advertisements and to analyse access to our website. Furthermore, our partners for online advertising receive pseudonymised information about your use of our website. cookie policy and privacy policy.
 
+0  
 
0
1473
4
avatar

What is the value of k if x3 + kx2 + 7x + 5 is divided by x + 6 and gives a remainder of −1?

 Feb 8, 2016

Best Answer 

 #2
avatar+105606 
+5

What is the value of k if x3 + kx2 + 7x + 5 is divided by x + 6 and gives a remainder of −1?

 

I am going to use remainder theorum.  :)

 

Here is one of many references for it if you want to take a look.

https://www.mathsisfun.com/algebra/polynomials-remainder-factor.html

 

\(f(x)=x^3+kx^2+7x+5\\ f(-6)=(-6)^3+k*(-6)^2+7*(-6)+5\\ f(-6)=-216+36k-42+5\\ f(-6)=-253+36k\\ But\;\;f(-6)=-1\\ -1=-253+36k\\ 252=36k\\ k=7\)

.
 Feb 8, 2016
 #1
avatar
0

What is the value of k if x3 + kx2 + 7x + 5 is divided by x + 6 and gives a remainder of −1?

 

[ x^3 + kx^2 + 7x + 5] / [ x + 6] = -1

 

x=1   and   k= -20, or

x=2   and   k=-8.75, or

x=3   and   k= -6 8/9

 Feb 8, 2016
 #2
avatar+105606 
+5
Best Answer

What is the value of k if x3 + kx2 + 7x + 5 is divided by x + 6 and gives a remainder of −1?

 

I am going to use remainder theorum.  :)

 

Here is one of many references for it if you want to take a look.

https://www.mathsisfun.com/algebra/polynomials-remainder-factor.html

 

\(f(x)=x^3+kx^2+7x+5\\ f(-6)=(-6)^3+k*(-6)^2+7*(-6)+5\\ f(-6)=-216+36k-42+5\\ f(-6)=-253+36k\\ But\;\;f(-6)=-1\\ -1=-253+36k\\ 252=36k\\ k=7\)

Melody Feb 8, 2016
 #3
avatar+104793 
0

Very nice, Melody  !!!!

 

 

 

cool cool cool

 Feb 8, 2016
 #4
avatar+105606 
0

Thanks Chris  :))

 Feb 8, 2016

4 Online Users