Bonjour,
a = 3x (x + 5)
= 3x * x + 3x * 5
= 3x² + 15x
b = -2x (x + 6)
= -2x * x - 2x * 6
= -2x² -12
c = -3x (4 - 5x)
= -3x * 4 - 3x * -5x
= -12x + 15x²
d = (1 + x) (1 + 2x)
= 1 * 1 + 1 * 2x + x * 1 + x * 2x
= 2 + 2x + 1x + 2x²
= 2 + 3x + 2x²
e = (x2 + 2)(x - 1)
= 2x * x + 2x * (-1) +2 * x + 2 * (-1)
= 2x² - 2x + 2x - 2
= 2x² -2
f = 2x (1 – 3x)
= 2x * 1 + 2x * (-3x)
= 2x - 6x²
En espèrant t'avoir aidé et bon courage!
