Question

If 3x+2y = 12 and xy = 6 find the value of 9x square + 4y square

Answer 1

Given,
3x+2y=12 , xy=6

(3x+2y)^2 =12^2

=9x^2+4y^2+12xy=144

ie, 9x^2+4y^2+(12×6)=144
=9x^2+4y^2+72=144

9x^2+4y^2=144-72
=72.
hope it helps to you.

Answer 2

$(3x + 2y) {}^{2} = (12) {}^{2} \\ = 9x {}^{2} + 4y {}^{2} + 2 \times 3x \times 2y = 144 \\ 9x {}^{2} + 4y {}^{2} + 12xy = 144$
now given XY =6 so
$12xy = 12 \times 6 = 72 \\ = = > 9x {}^{2} + 4y {}^{2} + 72 = 144 \\ so \: 9x {}^{2} + 4y {}^{2} = 144 - 72 \\ 9x {}^{2} + 4y {}^{2} = 72 \\ \\ by \: using \: the \: formula \: (a + b) {}^{2} = a {}^{2} + b {}^{2} + 2ab \\ hope \: it \: helps \: mark \: it \: brainliest \: plz$
plz mark it brainliest