Question

if x-1/x=7,find x^2-1/x^2​

Answer 1

Given: x + 1/x = 7

Squaring on both sides = (x + 1/x )2

=(7)2 = x2 + ( 1/x)2 + 2(x)(1/x) = 49

= (a+b)2= a2+b2 + 2ab] = x2 + 1/(x2) + 2 =

49 = x2 + 1/(x2) = 49 - 2

∴ x2 + 1/(x2)

= 47//