(2x+3y)^3-(2x-3y)^3 Simplify

2 min read Jun 16, 2024
(2x+3y)^3-(2x-3y)^3 Simplify

Simplifying the Expression: (2x+3y)^3 - (2x-3y)^3

This problem involves simplifying a difference of cubes expression. To do this, we can use the following algebraic identity:

a³ - b³ = (a - b)(a² + ab + b²)

Let's apply this identity to our given expression:

1. Identify a and b

In our case:

  • a = (2x + 3y)
  • b = (2x - 3y)

2. Substitute into the identity

(2x+3y)³ - (2x-3y)³ = [(2x + 3y) - (2x - 3y)][(2x + 3y)² + (2x + 3y)(2x - 3y) + (2x - 3y)²]

3. Simplify the expression

  • Simplify the first factor: (2x + 3y) - (2x - 3y) = 2x + 3y - 2x + 3y = 6y

  • Simplify the second factor:

    • (2x + 3y)² = 4x² + 12xy + 9y²
    • (2x + 3y)(2x - 3y) = 4x² - 9y²
    • (2x - 3y)² = 4x² - 12xy + 9y²

Therefore, the second factor becomes: 4x² + 12xy + 9y² + 4x² - 9y² + 4x² - 12xy + 9y² = 12x² + 9y²

4. Combine the simplified factors

(2x + 3y)³ - (2x - 3y)³ = (6y)(12x² + 9y²)

5. Further simplification

(2x + 3y)³ - (2x - 3y)³ = 72x²y + 54y³

Therefore, the simplified form of the expression (2x + 3y)³ - (2x - 3y)³ is 72x²y + 54y³.

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