bonjour
D = ( 2 x + 5 )² - ( x + 3 ) ( 2 x + 5 )
1. D = 4 x² + 20 x + 25 - ( 2 x² + 5 x + 6 x + 15 )
D = 4 x² + 20 x + 25 - 2 x² - 11 x - 15
D = 2 x² + 9 x + 10
2. D = ( 2 x + 5 ) ( 2 x + 5 - x - 3 )
D = ( 2 x + 5 ) ( x + 2 )
3. D = 2 ( 2/3)² + 9 *2/3 + 10
d = 8/9 + 18/3 + 10
D = 8/9 + 54/9 + 90/9 = 152/9
4. D = 0
( 2 x + 5 ) ( x + 2 ) = 0
x = - 5/2 ou - 2
5. D = 10
2 x² + 9 x + 10 = 10
2 x² + 9 x = 0
x ( 2 x + 9 ) = 0
x = 0 ou - 9/2
