Question

if x-1/x=5 find the value of x3-1/x3​

Answer 1

given

x - 1/x = 5

Now cubing both sides

( x- 1/x )³ = 5³

x³ - 1/x³ - 3(x -1/x) = 125

x³ - 1/x³ -3×5 =125

x³ - 1/x³ -15 = 125

x³ - 1/x³ =140