Question

find the value pls help

Answer 1

it may be help u..............

Answer 2

From the Question,

$\sf{4x {}^{2} + 9y {}^{2} = 69 \: \: and \: xy = 1 }$

To find the value of 2x+3y

Now,

$\sf{4x {}^{2} + 9y {}^{2} = 69 }$

Adding and subtracting 12xy,

$\implies \: \sf{4x {}^{2} + 9y {}^{2} + 12xy - 12xy = 69} \\ \\ \implies \: \sf{(2x + 3y) {}^{2} - 12xy = 69} \\ \sf{since \: xy = 1} \\ \implies \: \sf{(2x + 3y) {}^{2} = 69 + 12 } \\ \\ \implies \: \sf{2x + 3y = \sqrt{81}} \\ \\ \implies \: \huge{\tt{2x + 3y = 9}}$