To find a general formula for the \( n \)-th term of the sequence given:
- \( a_1 = 47 \)
- \( a_2 = 33 \)
- \( a_3 = 19 \)
- \( a_4 = 5 \)
- \( a_5 = -9 \)
we first observe the differences between consecutive terms.
- \( a_2 - a_1 = 33 - 47 = -14 \)
- \( a_3 - a_2 = 19 - 33 = -14 \)
- \( a_4 - a_3 = 5 - 19 = -14 \)
- \( a_5 - a_4 = -9 - 5 = -14 \)
The sequence has a constant difference of \(-14\), indicating that it is an arithmetic sequence.
The general form for the \( n \)-th term of an arithmetic sequence can be expressed as:
\[ a_n = a_1 + (n - 1) \cdot d \]
where:
- \( a_1 \) is the first term of the sequence,
- \( d \) is the common difference,
- \( n \) is the term number.
Substituting the values we have:
- \( a_1 = 47 \)
- \( d = -14 \)
Thus, the formula becomes:
\[ a_n = 47 + (n - 1)(-14) \]
We can simplify this expression:
\[ a_n = 47 - 14(n - 1) \] \[ a_n = 47 - 14n + 14 \] \[ a_n = 61 - 14n \]
Therefore, the equation to find the \( n \)-th term of the sequence is:
\[ a_n = 61 - 14n \]