Bonjour
Développer :
F=(3x+2)(2x-5)-(6x-5)(4x+2)
F = 6x² - 15x + 4x - 10 - (24x² + 12x - 20x - 10)
F = 6x² - 15x + 4x - 10 - 24x² - 12x + 20x + 10
F = 6x² - 24x² - 15x - 12x + 4x + 20x - 10 + 10
F = - 18x² - 3x
G=(4x-5)(2x-5)-(4x+1)(2x-3)
G = 8x² - 20x - 10x + 25 - (8x² - 12x + 2x - 3)
G = 8x² - 20x - 10x + 25 - 8x² + 12x - 2x + 3
G = 8x² - 8x² - 20x - 10x - 2x + 12x + 25 + 3
G = - 20x + 28
H=x²-2x(3x-1)
H = x² - 6x² + 2x
H = - 5x² + 2x.