Question

if
${x}^{2} + 1 \div {x}^{2} = 18$
Find x+1/x

Answer 1

${x}^{2} + \frac{1}{ {x}^{2} } = 18$
${(x \: + \frac{1}{x} )}^{2} - 2 \: = 18$
(x + 1/x)^2 = 20
x + 1/x = 2√5.