Factorize the following expression : \(4(x – y)^2 – 12(x – y)(x + y) + 9(x + y)^2\)

\[ 4(x – y)^2 – 12(x – y)(x + y) + 9(x + y)^2 \] \[ = [2(x – y)]^2 – 2[2(x – y)][3(x + y)] + [3(x + y)]^2 \] \[ = \left[2(x – y) – 3(x + y)\right]^2 \] \[ = (2x – 2y – 3x – 3y)^2 \] \[ = (-x – 5y)^2 \] \[ = (x + 5y)^2 \]