Réponse :
Bjr,
5(3a-6) + 2(4-6a)
= 15a-30 + 8 - 12a
= 3a-22
7(2-5a)+3(3-a)
= 14-35a+9-3a
= -38a+23
4(a-4) + 5(6-a)
= 4a-16+30-5a
= -a+14
8(7-6a) + 7(2+7a)
= 56-48a+14+49a
= a+70
6(10a-5)+20(2-3a)
= 60a-30+40-60a
= 10
2a(5-a) + 3a(4a-2)
= 10a-2a²+12a²-6a
= 10a²+4a
a(4a+6)+5a(1-2a)
= 4a²+6a+5a-10a²
= -6a²+11a
3[2a+5(1-a)+4]
= 3[2a+5-5a+4]
= 6a+15-15a+12
= -9a+27
a[3(a-3a)+2(3a-5)]
= a[3a-9a+6a-10]
= 3a²-9a²+6a²-10a
= -6a²+6a²-10a
= -10a
J'espère avoir pu vous aider