Question

calcule a soma doz dez primeiros termos PA 3,7,11

Answer 1

r = a2 - a1

r = 7 - 3

r = 4

3 , 7 ,11, 15, 19, 23, 27, 31, 35, 39

SOMA = 210

Answer 2

r= 4

a10: 3 + (10-1). 4
a10: 3+36= 39

S10= (3+39).10/2
S10= 42.5
S10: 210