Practicing Success
If $x^4+\frac{1}{x^4}=727, x>1$, then what is the value of $\left(x-\frac{1}{x}\right)$ ? |
6 -6 -5 5 |
5 |
If x4 + \(\frac{1}{x^4}\) = a then x2 + \(\frac{1}{x^2}\) = \(\sqrt {a + 2}\) = b and x - \(\frac{1}{x}\) = \(\sqrt {b - 2}\) If $x^4+\frac{1}{x^4}=727, x>1$ then x2 + \(\frac{1}{x^2}\) = \(\sqrt {727 + 2}\) = 27 and x - \(\frac{1}{x}\) = \(\sqrt {27 - 2}\) = 5 |