(x-1)(x-3)(x+5)(x+7)=297

3 min read Jun 17, 2024
(x-1)(x-3)(x+5)(x+7)=297

Solving the Equation (x-1)(x-3)(x+5)(x+7) = 297

This equation presents a challenge as it involves a product of four linear factors. Here's how we can solve it:

1. Expanding the Equation

The first step is to expand the product of the factors. This can be done in a few ways:

  • Pairwise Multiplication: Group the factors and multiply them in pairs:

    • [(x-1)(x-3)][(x+5)(x+7)]
    • This leads to (x² - 4x + 3)(x² + 12x + 35)
  • Direct Expansion: Multiply the terms one by one, being careful with the signs.

After expansion, we'll get a fourth-degree polynomial equation.

2. Simplifying the Equation

Once the expansion is done, simplify the polynomial equation by combining like terms. This will give us a standard form:

ax⁴ + bx³ + cx² + dx + e = 297

3. Transforming to a Standard Form

Subtract 297 from both sides to get a standard fourth-degree polynomial equation:

ax⁴ + bx³ + cx² + dx + (e - 297) = 0

4. Finding Roots (Solutions)

Finding the roots of a fourth-degree polynomial equation can be complex. There are several methods:

  • Factoring: Try to factor the polynomial into simpler expressions. This might not always be possible.
  • Rational Root Theorem: This theorem helps find potential rational roots. It involves checking factors of the constant term (e - 297) and the leading coefficient (a).
  • Numerical Methods: Methods like the Newton-Raphson method or graphical approaches can approximate the roots.

5. Solutions

The solutions to the equation (x-1)(x-3)(x+5)(x+7) = 297 represent the values of x that make the equation true. These solutions are called the roots of the equation.

Important Note: Solving a fourth-degree polynomial equation can be challenging. There might not be simple algebraic solutions, and numerical methods might be required to find approximate roots.

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