Question

Find value of x^2+1/x^2 when x+1/x=3

Answer 1

$x + \frac{1}{x} = 3 \\ \\ so \: {x}^{2} + \frac{1}{ {x}^{2} } = ( {x + \frac{1}{x} )}^{2} - 2.x. \frac{1}{x} \\ \\ = {3}^{2} - 2 \\ \\ = 9 - 2 \\ \\ = 7$

I hope this helps.