Bonjour, Vous pouvez m'aider de ces exercices merci j'ai vraiment besoin d'aide car je bloque

Bjr,

1)

5x² + 10x = 0

5x * 5x + 5x * 2 = 0

5x(2 + x) = 0

5x = 0

x = 0/5 = 0

et

2 + x = 0

x = 0 - 2 = -2

2)

x² - 81 = 0

(-9 + x)(9 + x) = 0

- 9 + x = 0

x = 0 + 9 = 9

et

9 + x = 0

x = 0 - 9 = - 9

3)

(x - 3)² - 49 = 0

x² - 6x + 9 - 49 = 0

x² - 6x - 40 = 0

(4 + x)(-10 + x) = 0

4 + x = 0

x = - 4

et

- 10 + x = 0

x = 0 + 10 = 10