Respuesta :

zexius
(9x - 8)(9x + 8)

9x × 9x = 81x²

9x × 8 = 72x

-8 × 9x = -72x

-8 × 8 = -64

= 81x² + 72x - 72x - 64

The 72x cancels out, so you're left with 81x² - 64.

The answer is 81x² - 64.