Réponse :
bonjour,
A = (2x + 5)( - 3x - 1) - 5(2 - x)
= -6x²-2x-15x-5 - ( 10 -5x )
= -6x²-2x-15x-5 -10 + 5x
= -6x² - 12x -15
B = 2( - 3x + 5) + (-3x + 7)(2x - 9)
= -6x + 10 + ( -6x²)+27x + 14x - 63
= -6x² +35x - 53
F = (5x + 8)(-3x - 7) + (9x - 4)( - 10 + 2x)
= -15x² - 35x -24x -56 + (-90x) + 18x²+ 40 - 8x
= -15x² -59x - 56 + 18x²-98x + 40
= 3x² - 157x - 16
voila:)
