if (y² + 1/(y²) ) = 167 and y > 0, find the value of ( y + 1/y ).

if (y² + 1/(y²) ) = 167 and y > 0, find the value of ( y +…

if (y² + $\frac{1}{y^2}$ ) = 167 and y > 0, find the value of ( y + $\frac{1}{y}$ ).

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Correct answer: A

Explanation

The correct answer is option 1 i.e. 13.

y² + 1/y² = 167

⇒ y² + 1/y² + 2 - 2 = 167

⇒ (y + 1/y)² - 2 = 167

⇒ (y + 1/y)² = 169

⇒ (y + 1/y) = 13