+0  
 
0
103
1
avatar+144 

For a certain value of \(k \), the system

\(\begin{align*} x + y + 3z &= 10, \\ -4x + 2y + 5z &= 7, \\ kx + z &= 3 \end{align*}\)

has no solutions. What is this value of \(k \)?

 Sep 25, 2018
 #1
avatar+96363 
+1

Multiply the first equation  by  -2  and we have

 

-2x  - 2y  - 6z  = -20     

-4x  + 2y + 5z  = 7          add these  and we get

 

-6x   - z    =  -13     (1)

kx  +   z   =      3

 

Multiply (1)  by - 1

 

6x + z  =  13

kx + z  = 3

 

This  system will have no solution  when k  =  6

 

 

cool cool cool

 Sep 25, 2018

21 Online Users

avatar
avatar
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.