(2x + y)² - (2y + x)² is equal to:

1. 3(x + y) (x - y)

2. 2(x - y) (x + y)

3. 2(y - x) (x + y)

4. (3x + y) (3x - y)

Using the formula

[∵ (x² - y²) = (x + y)(x - y)]

(2x + y)² - (2y + x)²

= ((2x + y) + (2y + x))((2x + y) - (2y + x))

= (2x + y + 2y + x)(2x + y - 2y - x)

= (2x + x + y + 2y)(2x - x + y - 2y)

= (3x + 3y)(x - y)

= 3(x + y)(x - y)

Hence, option 1 is the correct option.