Question

Descompuneți în factori (2x+1)^2-9
la sfarsir da 4(x-1)(x+2), cum? va rog trebuie acum ofer 55 puncte​

Answer 1

Formulă :

${a}^{2} - {b}^{2} = (a - b)(a + b)$

${(2x + 1)}^{2} - 9 = {(2x + 1)}^{2} - {3}^{2}$

$a = 2x + 1$

$b = 3$

$= (2x + 1 - 3)(2x + 1 + 3)$

$= (2x - 2)(2x + 4)$

$= 2(x - 1) \times 2(x + 2)$

$= 2 \times 2(x - 1)(x + 2)$

$= 4(x - 1)(x + 2)$

Answer 2

(2x + 1)² - 9 =

Folosim a² - b² = (a + b)(a - b)

= (2x + 1)² - 3²

= (2x + 1 + 3)(2x + 1 - 3)

= (2x + 4)(2x - 2)

= 2(x + 2)·2(x - 1)

= 4(x + 2)(x - 1)