Math Problem Statement

In the arithmetic sequence of -7,-4,-1,2 which term is 44?​​​​

Solution

To find which term in the arithmetic sequence is equal to 44, we can use the general formula for the nn-th term of an arithmetic sequence:

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

Where:

  • ana_n is the nn-th term,
  • a1a_1 is the first term,
  • dd is the common difference,
  • nn is the position of the term.

Step 1: Identify the first term a1a_1 and the common difference dd

  • a1=7a_1 = -7
  • The common difference dd is found by subtracting the first term from the second term: d=4(7)=3d = -4 - (-7) = 3

Step 2: Set up the equation to find nn

We are looking for the term that equals 44, so set an=44a_n = 44: 44=7+(n1)344 = -7 + (n - 1) \cdot 3

Step 3: Solve for nn

  1. Start by isolating the term involving nn: 44+7=(n1)344 + 7 = (n - 1) \cdot 3 51=(n1)351 = (n - 1) \cdot 3

  2. Divide both sides by 3: 513=n1\frac{51}{3} = n - 1 17=n117 = n - 1

  3. Finally, solve for nn: n=17+1=18n = 17 + 1 = 18

The term that equals 44 is the 18th term in the arithmetic sequence.

Would you like more details or have any questions?

Here are 5 related questions you might explore:

  1. How do you find the sum of the first 18 terms of this arithmetic sequence?
  2. What is the 25th term of this arithmetic sequence?
  3. How can you determine if a sequence is arithmetic or not?
  4. What happens to the general term formula if the common difference is negative?
  5. How do you find the common difference if only two non-consecutive terms are given?

Tip: When solving for nn in an arithmetic sequence, make sure to carefully isolate the variable by following each algebraic step methodically.

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Math Problem Analysis

Mathematical Concepts

Arithmetic Sequence

Formulas

Arithmetic sequence nth term formula

Theorems

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Suitable Grade Level

Grades 9-12