+0  
 
0
90
1
avatar

x+(1/x)=5

i) x=?

Guest May 29, 2017
Sort: 

1+0 Answers

 #1
avatar+75332 
+1

x + 1/x   = 5        multiply through by x

 

x^2  + 1  =  5x    subtract 5x from both sides

 

x^2  - 5x  +  1   = 0      subtract 1 from both sides

 

x^2 -5x  =  -1          take 1/2 of 5  = 5/2, square it  = 25/4  and add this to both sides

 

x^2  - 5x  +  25/4   =   -1 +  25/4       factor the left side, simplify the right

 

(x - 5/2)^2   =  21/4        take pos/neg roots 

 

x -  5/2   =  ± √ (21/4)  add 5/2 to both sides, simplify the right

 

x  =    ± √(21) / 2 +  5/2

 

x  = [  5 ± √21 ]  /  2

 

 

 

cool cool cool

CPhill  May 29, 2017

7 Online Users

avatar
We use cookies to personalise content and ads, to provide social media features and to analyse our traffic. We also share information about your use of our site with our social media, advertising and analytics partners.  See details