Question

os extremos de uma pa de cinco termo são 1e 13 qual e a soma de todos os termos dessa PA ​

Answer 1

$\displaystyle S_n=\frac{n(a_1+a_n)}{2}\\\\S_5=\frac{5(a_1+a_5)}{2}\\\\S_5=\frac{5(1+13)}{2}\\\\S_5=\frac{5(14)}{2}\\\\S_5=\frac{70}{2}\\\\S_5=35$