bonjour
f (x) = 2 ( x - 1 )² - 2 = 2 ( x² - 2 x + 1 ) - 2 = 2 x² - 4 x + 2 - 2 = 2 x² - 4 x
= forme canonique
f (x) = 2 x ( x - 2 ) = 2 x² - 4 x forme factorisée
2 x² - 4 x = forme développée
f (x) = 0
2 x ( x - 2 ) = 0
x = 0 ou 2
f (x) = 6
2 x² - 4 x = 6
2 x² - 4 x - 6 = 0
Δ = 16 - 4 ( 2 * - 6 ) = 16 + 48 = 64 = 8 ²
x 1 = ( 4 - 8 ) / 4 = - 4/4 = - 1
x 2 = ( 4 + 8 ) / 4 = 12 /4 = 3
tu peux finir maintenant
