Question

determine a soma dos termos de cada PA. (3,11,19,...115)

Answer 1

N= n1+(n-1).r. R=8 Sn= (A1+An)n = Sn=(3-115)16 = 112x16 = 896 115= 3+(n-1).8. 2. 2. 2 115-3= 7n 112=7n N= 16