Răspuns :
Sn= nxa1 +rxn(n-1) : 2, deci avem
S100= -100 + 5x100x99:2 = -100 + 24750 = 24650.
-------------------------------------------
Succes in continuare!
S100= -100 + 5x100x99:2 = -100 + 24750 = 24650.
-------------------------------------------
Succes in continuare!