bonjour
brevet dans 3 mois ..............
F = ( 3 x - 1 ) ( 3 x - 1 + 7 - x )
F = ( 3 x - 1 ) ( 2 x + 6 )
G = ( 2 x - 3 - 4 ) ( 2 x - 3 + 4 )
= ( 2 x - 7 ) ( 2 x + 1 )
f (x) = 6 x ( x - 5 ) - ( 7 - 3 x ) ( x - 5 )
f (x) = 6 x² - 30 x - ( 7 x - 35 - 3 x² + 15 x )
f (x) = 6 x² - 30 x - 7 x + 35 + 3 x² - 15 x
f (x) = 9 x² - 52 x + 35
f (x) = ( x - 5 ) ( 6 x - 7 + 3 x )
f (x) = ( x - 5 ) ( 9 x - 7 )
( x - 5 ) ( 9 x - 7 ) = 0
un facteur est nul
x = 5 ou 7/9
f ( 0 ) = 9 *0 - 52 *0 + 35 = 35
