Question

if x = 4 - root 15 then x^3 - 1/x^3

Answer 1

Answer:

-487.996

Step-by-step explanation:

Answer 2

Step-by-step explanation:

$x = 4 - \sqrt{15} \\ \\ = > \frac{1}{x} = 4 + \sqrt{15} \\ \\ {x}^{3} - \frac{1}{ {x}^{3} } = ( {x - \frac{1}{x} })^{3} + 3(x - \frac{1}{x}) = - 120 \sqrt{15} + 3( - 2 \sqrt{15}) = - 126 \sqrt{15}$