bonsoir
x
x²
x² - 4
on prend 4 on obtient 16 - 4 = 12
on prend 7 on obtient 49 - 4 = 45
on prend - 7 on obtient 49 - 4 = 45
x² - 4 = 0
x² = 4
x = √4 ou - √4
x = 2 ou - 2
f( - 1 ) = 1 - 4 = - 3
x² - 4 = 21
x² = 21 + 4 = 25
x = √25 ou - √5
x = 5 ou - 5
