Réponse :
Bonjour,
A = 2x(x + 5)
= 2x * x + 2x * 5
= 2x² + 10x
B = 2(4x + 2) - 4x(x - 3)
= 2 * 4x + 2 * 2 - 4x * x + 4x * 3
= 8x + 4 - 4x² + 12x
= 20x + 4 - 4x²
C = -2(3x + 4) - 4x(x - 3)
= -2 * 3x + (-2) * 4 - 4x * x + 4x * 3
= -6x + (-8) - 4x² + 12x
= 6x + (-8) - 4x²
D = x(x + 1) + 2x(x + 1)
= x * x + x * 1 + 2x * x + 2x * 1
= x² + 1x + 2x² + 2x
= 3x² + 3x
Bon courage ^-^
