Question

Determine 70 termo professora aritméticas (3.7,11)

Answer 1

$PA~~\{3;~7;~11;~...\}\\\\\\ a_1=3\\r\to~7-3=4 \\n=70\\ a_n=a_{70}=?\\\\\\ a_n=a_1+(n-1)\times r\\\\\\ a_{70}=3+(70-1)\times 4\to\\\\ a_{70}=3+69\times 4\to\\\\ a_{70}=3+276\to\\\\ \large\boxed{\boxed{a_{70}=279}}$