Hello,
Il faut utiliser la formule suivante : a(b + c) = ab + ac
-3(x + 7) = -3 * x - 3 * 7 = -3x - 21
4(2x - 3) = 4 * 2x + 4 * -3 = 8x - 12
-11(-x - 5) = -11 * -x - 11 * -5 = 11x + 55
x(2x + 9) = 2x * x + x * 9 = 2x² + 9x
-3x(6 + 4x) = -3x * 6 - 3x * 4x = -18x - 12x²
-2x(10 - 5x) = -2x * 10 - 2x * -5x = -20x + 10x²
