Répondre :
a)E= 5 - 10y + 3(5y - 1) - 7
=5-10y+15y-3-7
=5y-5
b)pour y=-2
a)E=5y-5
=5(-2)-5
=-10-5
=-15
b)pour y=3/5
E=5y-5
=5(3/5)-5
=15-5
=10
c)E=0
5y-5=0
5y=5
y=1
=5-10y+15y-3-7
=5y-5
b)pour y=-2
a)E=5y-5
=5(-2)-5
=-10-5
=-15
b)pour y=3/5
E=5y-5
=5(3/5)-5
=15-5
=10
c)E=0
5y-5=0
5y=5
y=1