bonjour
ta fonction est incorrecte
f (x) = ( x - 2 ) ² - 49
f (x) = x² - 4 x + 4 - 49 = x² - 4 x - 45
f (x) = ( x - 2 - 7 ) ( x - 2 + 7) = ( x - 9 ) ( x + 5 )
f ( 2/3) = ( 2/3 - 9 ) ( 2/3 + 5 ) = ( 2/3 - 27/3 ) ( 2/3 + 15 /3)
= - 25/3 * 17/3 = - 425/9
( x - 9 ) ( x + 5 ) = 0
point d'intersection ( - 5 ; 9 )
f ( 4) = ( 4 - 2 )² - 49 = 2² - 49 = 4 - 49 = 45 donc A ∉ courbe
( x - 2 )² - 49 = 15
( x - 2 )² = 15 + 49
( x - 2 )² = 64
( x - 2 ) = √64
( x - 2 ) = 8
x - 2 = 8
x = 8 + 2
x = 10
abscisse = 10