(4x+2y)^3 + (4x-2y)^3=16(ax^3+bxy^2)

2 min read Jun 16, 2024
(4x+2y)^3 + (4x-2y)^3=16(ax^3+bxy^2)

Expanding and Simplifying the Equation: (4x+2y)^3 + (4x-2y)^3 = 16(ax^3+bxy^2)

This problem involves expanding and simplifying a given algebraic expression to determine the values of constants 'a' and 'b'. Let's break down the steps:

1. Expanding the Cubes

We can use the following identity to expand the cubes: (a + b)³ = a³ + 3a²b + 3ab² + b³

Applying this to our equation:

(4x + 2y)³ = (4x)³ + 3(4x)²(2y) + 3(4x)(2y)² + (2y)³ = 64x³ + 96x²y + 48xy² + 8y³

(4x - 2y)³ = (4x)³ + 3(4x)²(-2y) + 3(4x)(-2y)² + (-2y)³ = 64x³ - 96x²y + 48xy² - 8y³

2. Adding the Expanded Terms

Now, let's add the two expanded expressions:

(64x³ + 96x²y + 48xy² + 8y³) + (64x³ - 96x²y + 48xy² - 8y³) = 128x³ + 96xy²

3. Simplifying and Comparing

The simplified expression on the left side is 128x³ + 96xy². Let's compare this to the right side of the original equation, 16(ax³ + bxy²):

128x³ + 96xy² = 16(ax³ + bxy²)

To make both sides equal, we need:

  • 16a = 128
  • 16b = 96

4. Solving for a and b

Dividing both sides of the equations by 16, we get:

  • a = 8
  • b = 6

Therefore, the values of a = 8 and b = 6 satisfy the given equation.

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