Question

full formula of this question ​

Answer 1

Step-by-step explanation:

use the formula (a - b)² = a² + b² - 2ab.

Here a = y , b= 1/y.

Therefore (y - 1/y)² = y² + 1/y² - 2

(y - 1/y)² = 11 - 2 = 9

therefore taking square root on both sides,

y - 1/y = ± 3

Answer 2

3

Step-by-step explanation:

${(y - \frac{1}{y} )}^{2} \\ = {y}^{2} + \frac{1}{ {y}^{2} } - 2 \times \frac{1}{y} \times y \\ = 11 - 2 \\ = 9$

A/C

${ ({y} - \frac{1}{y} )}^{2} = 9 \\ = > y - \frac{1}{y} = 3$

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