Question

X^4+1/x^4= 6239, find x+1/x pls quick

Answer 1

hello users ....

solution:-
we know that :-
x² + y² = ( x+y)² - 2xy

Here,
X^4+1/x^4=(x²)² + 1/ (x²)²

=  (x² + 1/x²)² - 2* x² * 1/x²

=> 6239 = (x² + 1/x²)² - 2 

=> 6239 + 2 = (x² + 1/x²)² 

=> (x² + 1/x²)²  = 6241 = 79²

=> (x² + 1/x²) = 79 

Now, Again..
(x² + 1/x²) = (x + 1/x )² - 2*x * 1/x

=> 79 = (x + 1/x )² - 2

=> 79 + 2 = (x + 1/x )² 

=> (x + 1/x )²  = 81 = 9²

=> (x + 1/x ) = 9 Answer 

## hope it helps :)