Question

How to solve this sum it is very difficult

Answer 1

hope this may help u..

log((x+y)/3)=1/2(logx+logy)  

=> 2 log((x+y)/3) = log(x) + log(y)  

=> 2 log((x+y)/3) = log(x y)  

=> [(x + y)/3]^2 = xy  

=> (x + y)^2 = 9xy  

=> x^2 + y^2 + 2xy = 9xy  

=> x^2 + y^2 = 7xy  

divide by xy  

=> (x/y) + (y/x) = 7