Question

If
$x + \frac{1}{x} = 9$
find the value of
$x^{4} + \frac{1}{x^{4} }$
​

Answer 1

x^4 + 1/x^4.

( x^2 + 1/x^2) - 2

( x+ 1/x)^2 -4

(9)^2 -4

81 -4

77