+0  
 
0
37
2
avatar

Let x and y be real numbers such that xy=9 Find the set of all possible values of x+y

 May 24, 2021
 #1
avatar+1782 
0

I think since sqrt(9) = +- 3, it can be all numbers other than -6 to 6  (non inclusive)

 

=^._.^=

 May 24, 2021
 #2
avatar+176 
+1

Use AM-GM for positive x,y, we can get that x+y>=6, and for negatives x+y<=-6.

 

So, it is either x+y>=6 or x+y<=-6.

 May 24, 2021

49 Online Users

avatar
avatar
avatar
avatar
avatar
avatar