Question

If x+1/x=a, prove that (x-1/x)²=a²-4 with proper formula and rough work​

Answer 1

$x + \frac{1}{x} = a \\ ( {x + \frac{1}{x} })^{2} = {a}^{2} \\ ( {x - \frac{1}{x} })^{2} + 4 = {a}^{2} \\ ( {x - \frac{1}{ x } })^{2} = {a}^{2} - 4$