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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