If $\left(2 x-\frac{3}{x}\right)=2$, then what is the value of $\left(16 x^4+\frac{81}{x^4}\right) ?$
Answer & explanation
Correct answer: option 3
If $(x - \frac{1}{x}) = n$
(x2 + x-2) = (n)2 + 2 = b
= (x4 + x-4) = b2 - 2
According to the question,
$\left(2 x-\frac{3}{x}\right)=2$
$\left(4 x^2+\frac{9}{x^2}\right) $ = (2)2 + 2 × 2 × 3 = 16
$\left(16 x^4+\frac{81}{x^4}\right)$ = 162 - 2 × 2 × 3 × 2 × 3
$\left(16 x^4+\frac{81}{x^4}\right)$ = 256 - 72 = 184