Bonjour,
1)
2 -8 +4 +3
2)
-7 +3 +5 -4
a= 2-5 = -3
b= -3 +7 +3 = 7
c= -7 -2 +4 -1 = -6
d= -3+4 = 1
e= 7+2 +4 = 13