Question

calcular a soma dos termos da PA 5,8..74

Answer 1

74=5+(n-1)3
74=5+3n-3
74=3n+2
3n=74-2
3n=72/
n=72/3
n=24

Sn=5+74.24/2
Sn=79.24/2
sn=1896/2
sn=948

Soma = 948