Find the Position of 18 in the Sequence 4n-2: Term Identification

To determine if the number 18 is part of the series described by the formula $a_n = 4n - 2$, follow these steps:

• Step 1: Set up the equation $4n - 2 = 18$.
• Step 2: Solve for $n$ by first adding 2 to both sides: $4n = 20$.
• Step 3: Divide both sides by 4 to isolate $n$: $n = 5$.

We have found $n = 5$, which is an integer, indicating that 18 is indeed part of the series $4n - 2$, where $n$ is a positive integer. Thus, the element 18 is in the 5th position of the series.

Therefore, the number 18 is part of the series, and it is the 5th element.

The correct answer, based on the choices provided, is: Yes, $5$.