bonsoir
5 x² - 3 x - 2 = 0
Δ = ( - 3 )² - 4 ( 5 * - 2 ) = 9 + 40 = 49 = 7 ²
x 1 = ( 3 - 7 ) / 10 = - 4 /10 = - 2 /5
x 2 = ( 3 + 7 ) / 10 = 1
5 ( x + 2 /5 ) ( x - 1 ) = 0
x = - 2/5 ou 1
x² + 7 x + 6 = 0
Δ = 49 - 4 ( x * 6 ) 49 - 24 = 25 = 5 ²
x 1 = ( - 7 - 5 ) / 2 = - 6
x 2 = ( - 7 + 5 ) / 2 = - 1
(x + 6 ) ( x + 1 ) = 0
x = - 6 ou - 1
2 x² - x - 6 = 0
Δ = 1 - 4* - 12 = 1 + 48 = 49 = 7 ²
x 1 = ( 1 + 7 ) / 4 = 2
x 2 = ( 1 - 7 ) / 2 = - 3
racines = 2 et - 3
