bonjour
f(3) = -1
f (6) = 0
( 0 + 1 ) : ( 6 - 3 ) = 1 /3
ax = x /3
f ( 3 ) = - 1
3 * 1/3 + b = - 1
3 /3 + b = - 1
b = - 1 - 1 = - 2
f (x) = x /3 - 2
d'où f ( 6) = 6 * 1/3 - 2 = 6 /3 - 2 = 2 - 2 = 0
4 x² - 12 x + 9 + ( 2 x - 3 ) ( x - 4 )
= ( 2 x - 3 )² + ( 2 x - 3 ) ( x - 4 )
= ( 2 x - 3 ) ( 2 x - 3 + x - 4 )
= ( 2 x - 3 ) ( 3 x - 7 )
