# How do you write an explicit rule for the sequence 3,5,7,9,...?

Apr 30, 2018

${a}_{n} = 3 + 2 \left(n - 1\right)$

#### Explanation:

Find the common difference $d$:
$d = 5 - 3 = 2$

Write the rule:
${a}_{n} = {a}_{1} + d \left(n - 1\right)$

${a}_{n} = 3 + 2 \left(n - 1\right)$