Question

if x=5-2√6 , find x²+1/x²

Answer 1

x = 5-2√6
or 1/x = 1/5-2√6
= 5+2√6
Now x^2 + 1/x^2 =(5-2√6)^2 + (5+2√6)^2
= 25-20√6+24+25+20√6+24
= 98