Question

determine a soma dos 14 termo da PA ( 3,10,17...)​

Answer 1

$> resolucao \\ \\ \geqslant progressao \: aritmetica \\ \\ r = a2 - a1 \\ r = 10 - 3 \\ r = 7 \\ \\ a14 = a1 + 13r \\ a14 = 3 + 13 \times 7 \\ a14 = 3 + 91 \\ a14 = 94 \\ \\ \geqslant soma \: dos \: termos \: da \: pa \\ \\ sn = \frac{(a1 + an)n}{2} \\ \\ sn = \frac{(3 + 94)14}{2} \\ \\ sn = \frac{97 \times 14}{2} \\ \\ sn = 97 \times 7 \\ \\ sn = 679 \\ \\ > < > < > < > < > < > < >$