Question

x2 + 1/x² = 27 find x​

Answer 1

Step-by-step explanation:

[x - 1/x]² = x² + 1/x² - 2

=> [x - 1/x]² = 25

=> x - 1/x = 5

=> x² - 1 = 5x

=> x² - 5x - 1 = 0

=> x = 5 ± √(25 + 4)/ 2

=> x = [5 ± √29] / 2

=> x = [5 + √29]/2 and x = [5 - √29]/2

Answer 2

Answer:

$2x + \frac{1}{ {x}^{2} } = 27$

$\frac{2 {x }^{3} + 1 }{ {x}^{2} } = 27$

$2 {x}^{3} + 1 = 27 \times {x}^{2}$

$2 {x}^{3} + 1 = 27 {x}^{2}$

$27 {x}^{3} - 2 {x}^{2} - 1 = 0$

Factorise it and this is answer