Question

Quanto da essa conta : (3x - 4y) . (3x + 4y) ??? ( 16 pontos )

Answer 1

(3x)(3x) + (3x)(-4y) + (4y)(3x) + (4y)(-4y) 
9x² - 12xy + 12xy - 16y² 
Resposta: 9x² - 16y² 

Answer 2

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

3x . 3x + 3x . 4y - 4y.3x - 4y.4y

9x² + 12xy - 12xy - 16y²

=> 9x² - 16y²