bonjour
1
1 x 2 = 2
2 - 5 = - 3
1
1 x 3 = 3
3 + 2 = 5
- 3 x 5 = - 15
x
2 x
2 x - 5
x
3 x
3 x + 2
on obtient B = ( 2 x - 5 ) ( 3 x + 2 )
D = ( 3 x + 2 )² - ( x + 7 ) ( 3 x + 2 )
= 9 x² + 12 x + 4 - ( 3 x² + 2 x + 21 x + 14 )
= 9 x² + 12 x + 4 - 3 x² - 23 x - 14
= 6 x² - 11 x - 10
B = 6 x² + 4 x - 15 x - 10
= 6 x² - 11 x - 10
donc elle a raison
