Question

Qual a soma dos 70 termos do PA (3,9,15....417)?
preciso de ajuda gente​

Answer 1

$> resolucao \\ \\ \geqslant progressao \: aritmetica \\ \\ sn = \frac{(a1 + an)n}{2} \\ \\ sn = \frac{(3 + 417)70}{2} \\ \\ sn = \frac{420 \times 70}{2} \\ \\ sn = 420 \times 35 \\ \\ sn = 14700 \\ \\ \\ > < > < > < > < >$