Question

If x${}^2$+(1/x${}^2$) = 11, then the value of x${}^3$-(1/x${}^3$) =?

• A. 36
• B. -36
• C. Can’t be determined
• D. Both 36 and -36
• E. None of these

Answer 1

The correct option is D

Both 36 and -36

$x^2+\left(\frac{1}{x^2}\right)=11,{(x-\frac{1}{x})}^2=9,x-\frac{1}{x}=\pm 3$

$x^3-\frac{1}{x^3}=\pm 27\pm 9=\pm 36$