Bonjour
Développer et réduire :
-1/2x (4x+8)
= - 4/2x² - 8/2x
= - 2x² - 4x
(5+1/2x)(1-4x)x
= (5 - 20x + 1/2x - 4/2x) x
= (5 - 20x + 0,5x - 2x) x
= 5x - 20x² + 0,5x² - 2x²
= 18,5x² + 5x.
(3x²-1)(x+5)
= 3x³ + 15x² - x - 5
3(x-2)(2x+1)
= 3 (2x² + x - 4x - 2)
= 6x² + 3x - 12x - 6
= 6x² - 9x - 6.
