Math Problem Statement

If the common difference in an arithmetic sequence is -3, and the first term is 7, what is the 14th term?

Solution

The problem asks us to find the 14th term of an arithmetic sequence where:

  • The first term (a1a_1) is 77,
  • The common difference (dd) is 3-3.

The formula for the nnth term of an arithmetic sequence is:

an=a1+(n1)da_n = a_1 + (n-1) \cdot d

Substitute the given values:

a14=7+(141)(3)a_{14} = 7 + (14-1) \cdot (-3)

Simplify:

a14=7+13(3)a_{14} = 7 + 13 \cdot (-3) a14=739a_{14} = 7 - 39 a14=32a_{14} = -32

Thus, the answer is: A. 32\text{A. } -32

Would you like a detailed explanation of the steps or help with related concepts? Here are five follow-up questions:

  1. How can the general formula for arithmetic sequences be derived?
  2. What happens if the common difference (dd) is positive instead of negative?
  3. Can you derive the sum of the first nn terms of this sequence?
  4. How does the position (nn) affect the growth or decline of the sequence?
  5. What are some real-world examples of arithmetic sequences?

Tip: Always double-check calculations when working with negative numbers to avoid errors!

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Math Problem Analysis

Mathematical Concepts

Arithmetic Sequences
Algebra

Formulas

an = a1 + (n-1) * d

Theorems

Arithmetic Sequence Formula

Suitable Grade Level

Grades 6-8