Hasan Naqvi
Last Activity: 9 Years ago
let x + 1/x =n
then
(x + 1/x) 3 =n3
= x3 + 1/x3 + 3 * x * 1/x2 + 3 * x2 * 1/x
=110 + 3/x + 3x
=110 + 3(x + 1/x )
=110 + 3n
Now solving,
n3= 110 +3n
n3 – 3n -110 = 0
Putting n =5(one of the factors of 110), we this eqn to reduce to 0
So dividing this equation by n-5
(n-5)(n2 - 5n + 22) = 0
Since the quadratic equation has no real answer,
I guess x + 1/x = 5