Question

Pls tell the answer of this question...Pls​

Answer 1

Answer:

50

Step-by-step explanation:

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Answer 2

Given:

$\sf3y - \dfrac{1}{3y} = 7$

To find:

$\sf9{y}^{2} + \dfrac{1}{9 {y}^{2} }$

$\:$

Solution:

We have,

$\sf3y - \dfrac{1}{3y} = 7$

$\bigstar {\mathfrak {\pink {On\ squaring\ both\ the\ sides.}}}$

$\sf(3y - \dfrac{1}{3y})^{2} = (7)^{2}$

$\bigstar {\mathfrak {\red {Using\ identity\ (a-b)^{2} = a^{2} -2ab + b^{2}}}}$

$\sf(3y)^{2} - 2 \times 3y \times \dfrac{1}{3y} + { (\dfrac{1}{3y} })^{2} = (7)^{2}$

$\sf9y^{2} - 2 \times \cancel{3y} \times \dfrac{1}{\cancel{3y}} + { \dfrac{1}{9y^{2} } } = 49$

$\sf9y^{2} - 2 + { \dfrac{1}{9y^{2} } } = 49$

$\sf9y^{2} + { \dfrac{1}{9y^{2} } } = 49 + 2$

${\boxed {\bf {\purple{9y^{2} + { \dfrac{1}{9y^{2} } } = 51}}}}$

$\:$

Answer:

∴ Value of $\sf9{y}^{2} + \dfrac{1}{9 {y}^{2} }$ is ${\underline {\mathcal {\green {51}}}}$