Răspuns:
a+b+c+d+e+f+g=-7
a,b,c,d,e,f,g=nr.consecutive
b=a+1
c=b+1=a+2
d=c+1=a+3
e=d+1=a+4
f=e+1=a+5
g=f+1=a+6
a+a+1+a+2+a+3+a+4+a+5+a+6=-7
7a+21=-7
7a=-7-21
7a=-28
a=-28:7
a=-4
b=-4+1=-3
c=-3+1=-2
d=-2+1=-1
e=-1+1=0
f=0+1=1
g=1+1=2
Verificare :
(-4)+(-3)+(-2)+(-1)+0+1+2=-10+3=-7
