Réponse :
Bonjour,
a. 3x= 9
3x/3 = 9/3
x= 3
b. 5y = 3
5y / 5 = 3 / 5
y = 3/5
c. 4z = -7
4z/4 = -7/4
z = -7/4
d. -2z = -8
-2z/-2 = -8/-2
z = 8/2
z = 4
e.7x = 4
7x / 7 = 4/7
x = 4/7
f. -y = -7.2
-y * -1 = -7.2 * -1
y = 7.2
a toi les trois derniers ;)
Bon courage.