Math Problem Statement

The first three terms of a geometric sequence are x+2 2x and 4x-6. In no more than 5 steps, determine the common ratio of this sequence

Solution

To determine the common ratio rr of the geometric sequence with terms x+2x+2, 2x2x, and 4x64x-6, we can proceed as follows:

Solution Steps:

  1. Identify the property of a geometric sequence:
    For any three consecutive terms aa, arar, and ar2ar^2 in a geometric sequence, the ratio of consecutive terms is constant. Thus: 2xx+2=4x62x\frac{2x}{x+2} = \frac{4x - 6}{2x}

  2. Set up the first ratio equation: 2xx+2=4x62x\frac{2x}{x+2} = \frac{4x - 6}{2x}

  3. Cross-multiply to eliminate the fractions: 2x2x=(x+2)(4x6)2x \cdot 2x = (x + 2)(4x - 6) [ 4x^2 = 4x^2 - 6x + 8x -12

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Math Problem Analysis

Mathematical Concepts

Algebra
Geometric Sequences
Ratios

Formulas

Common ratio of a geometric sequence: r = T(n+1) / T(n) where T(n) and T(n+1) are consecutive terms

Theorems

Properties of geometric sequences: In a geometric sequence, the ratio between consecutive terms is constant.

Suitable Grade Level

Grades 9-10