bonjour
A (x) = ( 2 x + 3 ) ( 3 x - 3 ) - ( 6 x - 2 ) ( 2 x + 3 )
A (x) = 6 x² - 6 x + 9 x - 9 - ( 12 x² + 18 x - 4 x - 6 )
A (x) = 6 x² + 3 x - 9 - 12 x² - 14 x + 6
A (x) = - 6 x² - 11 x - 3
si x = 0 , A (x) = - 3
A (x) = ( 2 x + 3 ) ( 3 x - 3 - 6 x + 2 )
A (x) = ( 2 x + 3 ) ( - 3 x - 1 )
A (x) = 0 quand x = - 3/2 ou - 1/3
A (x) > 0
x - ∞ - 3/2 - 1/3 + ∞
2 x + 3 - 0 + +
- 3 x - 1 + + 0 -
produit - 0 + 0 -