Sagot :
Bonjour,
C = (2x - 1)(x - 5) + (3x + 7)(x - 5)
(x-5) ( 2x-1 +3x +7 )
= (x-5) ( 5x +6)
D = (2x + 5)(x - 3) + (2x + 5)(-3x + 1)
(2x+5) ( x-3 -3x +1)
= (2x+5) ( -2x -2)
E = (3x + 7)(2x - 9) - (3x + 7)(5x - 7)
(3x+7) ( 2x-9 -5x +7)
= (3x+7) ( -3x -2)