bonsoir
A (x) = ( x - 4 )² - 25 ⇒ forme 1
A (x) = x² - 8 x + 16 - 25 = x² - 8 x - 9 ⇒ forme 2
A ( x) = ( x - 9 ) ( x + 1 ) = x² + x - 9 x - 9 = x² - 8 x - 9 ⇒ forme 3
A (x) = 0
( x - 9 ) ( x + 1 ) = 0
x = 9 ou - 1
A (x) = - 25
( x - 4 )² - 25 = - 25
( x - 4 )² = 0
x = 4
A (x) = - 8 x
x² - 8 x - 9 = - 8 x
x² - 9 = 0
( x - 3 ) ( x + 3 ) = 0
x = 3 ou - 3
A (x) = - 9
x² + 8 x - 9 = - 9
x² + 8 x = 0
x ( x + 8 ) = 0
x = 0 ou - 8
