An investment of 12,000 dollars grows to 18,000 dollars in 6 years. Which equation correctly represents the first step to find the annual interest rate, $r$?

$(1 + r)^6 = \frac{18000}{12000}$

$1 + r = \frac{18000}{12000 \times 6}$

Interest-ing Problems Practice — Grade 4 amc_math