Math Problem Statement

Find x so that x+1, x-1, and 2x are terms of an arithmetic sequence. Write out the terms

Solution

For x+1x+1, x1x-1, and 2x2x to be terms of an arithmetic sequence, the difference between consecutive terms must be the same. This gives us the condition:

(x1)(x+1)=2x(x1)(x - 1) - (x + 1) = 2x - (x - 1)

Step 1: Simplify the equation

The first term on the left side simplifies as: (x1)(x+1)=x1x1=2(x - 1) - (x + 1) = x - 1 - x - 1 = -2

The right side simplifies as: 2x(x1)=2xx+1=x+12x - (x - 1) = 2x - x + 1 = x + 1

Step 2: Set up the equation

Now we equate the two expressions: 2=x+1-2 = x + 1

Step 3: Solve for xx

Subtract 1 from both sides: 21=x-2 - 1 = x x=3x = -3

Step 4: Verify the terms

Substitute x=3x = -3 into the terms:

  • x+1=3+1=2x + 1 = -3 + 1 = -2
  • x1=31=4x - 1 = -3 - 1 = -4
  • 2x=2(3)=62x = 2(-3) = -6

The terms are 2-2, 4-4, and 6-6. The common difference is 2-2, confirming that the terms form an arithmetic sequence.

Thus, x=3x = -3, and the terms are 2-2, 4-4, and 6-6.

Would you like further details on this solution?

Related Questions:

  1. What are the general conditions for numbers to form an arithmetic sequence?
  2. How would the problem change if the sequence was geometric?
  3. How do you find the sum of an arithmetic sequence?
  4. Can an arithmetic sequence have increasing terms if one term is negative?
  5. How does solving for terms in an arithmetic sequence apply to real-world scenarios?

Tip:

When working with sequences, always check for the common difference (arithmetic) or ratio (geometric) to confirm the type of sequence.

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Math Problem Analysis

Mathematical Concepts

Algebra
Arithmetic Sequences

Formulas

Arithmetic sequence difference: d = a(n+1) - a(n)

Theorems

Properties of Arithmetic Sequences

Suitable Grade Level

Grades 8-10