Respuesta :
3; 8; 13; 18;..
TN = T1 + (N-1)R
T20 = 3 + (20 - 1)(5)
T20 = 3 + (19)(5)
T20 = 3 + (95)
T20 = 98
SUMA
[tex]S = \frac{(TN+T1)N}{2}\\\\S = \frac{(98+3)(20)}{2}\\\\S = \frac{(101)(20)}{2}\\\\S = (101)(10)\\\\S = 1010[/tex]
Eternamente
☆꧁☆༒ axllxa ༒☆꧂☆