Question

(x+1/x)=4 find (x-1/x)

Answer 1

x+1/x=4
x^2+1/x^2+2=16
x^2+1/x^2 =14
x^2+1/x^2-2=12
(x-1/x)^2=12
x-1/x=2root 3

Answer 2

(x+1/x)^2=x^2+1/x^2+2×x×1/x

;4^2=x^2+1/x^2+2

;x^2+1/x^2=14

again
(x-1/x)^2=x^2+1/x^2-2×x×1/x

(x-1/x)^2=14-2

;x-1/x=√12

;x-1/x=2√3

is your answer