bonjour
f (x) = 2 x² - 4 x - 6
g ( x) = 2 ( x - 1 )² - 8
h (x) = 2 ( x + 1 ) ( x - 3 )
g (x) = 2 ( x² - 2 x + 1 ) - 8
g ( x) = 2 x² - 4 x + 2 - 8
g ( x ) = 2 x² - 4 x - 6
h (x) = ( 2 x + 2 ) ( x - 3 )
h ( x) = 2 x² - 6 x + 2 x - 6
h (x) = 2 x² - 4 x - 6
antécédents de 0
( 2 x + 2 ) ( x - 3 ) = 0
donc x = - 2/2 = - 1 ou 3
antécédent de - 6
2 x² - 4 x - 6 = - 6
2 x² - 4 x - 6 + 6 = 0
2 x ( x - 2 ) = 0
x = 0 ou 2
f ( 0) = - 6
f (3) = 18 - 12 - 6 = 0
f ( √2 ) = 2 (√ 2)² - 4 √2 - 6 = 4 - 4 √2 - 6 = - 2 - 4 √2
voilà , termine
