Question

If x+1 x = 5 , then evaluate x 4 +1 x 4

Answer 1

$x+\frac{1}{x}=5\\\\x^2+\frac{1}{x^2}+2*x*\frac{1}{x}=5^2=25\\\\x^2+\frac{1}{x^2}=23\\\\square\ again\\\\x^4+\frac{1}{x^4}+2=23^2\\\\answer=527$