Question

plz answer the following question
7th question

Answer 1

$Given : 2x - \sqrt{7} y = 10$

On Squaring both sides, we get

$= \ \textgreater \ (2x - \sqrt{7}y)^2 = (10)^2$

$= \ \textgreater \ 4x^2 + 7y^2 - 4 \sqrt{7}xy = 100$

$= \ \textgreater \ 4x^2 + 7y^2 - 4 \sqrt{7} ( -\sqrt{7} ) = 100$

$= \ \textgreater \ 4x^2 + 7y^2 + 4(7) = 100$

= > 4x^2 + 7y^2 + 28 = 100

= > 4x^2 + 7y^2 = 100 - 28

= > 4x^2 + 7y^2 = 72.



Hope this helps!