Bonjour,
(-1,5x-3) (4x-0,5)
= - 6x² + 0,75x - 12x + 1,5
= - 6x² - 11,25x + 1.5
(8x-7) (-7x+7)
= - 56x² + 56x + 49x - 49
= - 56x²+ 105x - 49
(4z+3)^2
= 16z² + 24z + 9
6+(5y-2)(3-4y)
= 6 + 15y - 20y² - 6 + 8y
= - 20y² + 23y
5z-(4z+3)(-2z-5)
= 5z - (- 8z² - 20z - 6z - 15)
= 5z + 8z² + 20z + 6z + 15
= 8z² + 31z + 15
6(2x-1)(3-x)
= 6 (6x - 2x² - 3 + x)
= 36x - 12x² - 18 + 6x
= - 12x² + 42x - 18.
