Description for Correct answer:
Given equations are

\( \Large 3x + 2y = 12 \) ...(i)

\( \Large XY = 6 \) ...(ii)

On squaring Eq. (i) on both sides, we

\( \Large \left(3x + 2y\right)^{2} = \left(12\right)^{2} \)

=> \( \Large 9x^{2} + 4y^{2} + 12xy = 144 \)

=> \( \Large 9x^{2} + 4y^{2} = 144 - 12xy \)

= \( \Large 144 - 12 \left(6\right) = 144 - 72 = 72 \)