Question

if x-1/x=5 then x3-1/X3 EQUALS

Answer 1

$x {}^{3} - \: \frac{1}{x {}^{3} } = 140$
hope it helps ... :)

Answer 2

Given that x - 1/x = 5

Cubing on both sides, we get

(x - 1/x)^3 = (5)^3

x^3 - 1/x^3  - 3 * x * 1/x(x - 1/x) = 125

x^3 - 1/x^3 - 3(x - 1/x) = 125

x^3 - 1/x^3 = 125 + 3(x - 1/x)

x^3 - 1/x^3 = 125 + 3(5)

x^3 - 1/x^3 = 125 + 15

x^3 - 1/x^3 = 140.


Hope this helps!