+0  
 
0
149
1
avatar

the square root of (x+15) + (square root of x) =15, what is the value of "x".

Guest Aug 1, 2017
Sort: 

1+0 Answers

 #1
avatar+79894 
+1

 

sqrt ( x + 15)  +  sqrt (x)  = 15              subtract sqrt (x) from both sides

 

sqrt ( x + 15)   = 15  - sqrt (x)               square both sides

 

x + 15  =     225  - 30 sqrt (x)  + x        subtract x from both sides

 

15  = 225  - 30sqrt(x)                           rearrange as

 

30sqrt (x)  =  210                               divide both sides by 30

 

sqrt (x)  = 7                                         square both sides again

 

x  = 49

 

Check  

 

sqrt ( 49 + 15 )  + sqrt (49)  = 15   ???

 

sqrt (64)  + sqrt (49)   = 15   ??

 

8 + 7  = 15      OK!!!

 

 

 

cool cool cool

CPhill  Aug 1, 2017

9 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