[tex] {(2x + y)}^{2} - {(2x - y)}^{2} [/tex]
Ai doua metode: ori desfaci fiecare binom in parte fie folosesti formula:
[tex] {x}^{2} - {y}^{2} = (x - y)(x + y)[/tex]
[tex]((2x + y) - (2x - y))(2x + y + 2x - y) \\ (2x + y - 2x+ y) \times 4x \\ 2y \times 4x \\ 8xy[/tex]