9. The \( n \)th sum of a sequence is Sn \( =n^{2}+4 n \). Ihat is the 6 th sum of the sequence

To find the 6th sum of the sequence, simply substitute \( n = 6 \) into the formula \( S_n = n^2 + 4n \). Calculating that gives: \[ S_6 = 6^2 + 4 \times 6 = 36 + 24 = 60. \] So, the 6th sum of the sequence is 60. Now, let’s have some fun! Did you know that sequences like this can model real-world phenomena? For example, quadratic sequences can represent situations where growth accelerates, like the distance covered by a car accelerating on a straight road. So, next time you're in a car, think about how your speed changes and how it could be described with a sequence! And speaking of sequences, it’s easy to make a mistake by mixing up the sequence numbers! A common oops is calculating the sum for the wrong term. Always double-check that you’re substituting the right value for \( n \). This simple step can save you from a head-scratching mystery of wrong answers!