Question

O 8° termo da PA é 15 e o A1=1. Qual a razão?

Answer 1

$a_8=15\\n=8\\a_1=1\\r=?\\\\\\ a_n=a_1+(n-1)*r\\\\\\ 15=1+(8-1)*r\to\\\\ 15= 1+7r\to\\\\ 15-1=7r\to\\\\ 14=7r\to\\\\ \dfrac{14}{7} =r\to\\\\ \large\boxed{r=2}$