Réponse :
Bonsoir,
Développement et réduction des expressions :
A = 3(x - 1) + 2(2 - x)
= 3 * (x - 1) + 2 * (2 - x)
= 3 * x - 3 + 2 * 2 - 2 * x
= 1 + x
B = 2 – 7(2 - x)
= 2 - 7 * (2 - x)
= 2 - (7 * 2 - 7 * x)
= -12 + 7 * x
C = - (2 - a) – (-5a + 4)
= - (2 - a) - (-5 * a + 4)
= -2 + a - (-5 * a + 4)
= -6 + 6 * a
Bon courage ^-^
