(x+1)(x+9)(x+5)^2+63

4 min read Jun 16, 2024
(x+1)(x+9)(x+5)^2+63

Factoring and Solving the Expression (x+1)(x+9)(x+5)^2 + 63

This article explores the process of factoring and solving the expression (x+1)(x+9)(x+5)^2 + 63.

Understanding the Expression

The given expression is a polynomial with a degree of 5, meaning it has five possible roots. It's a combination of linear and squared factors, making it potentially challenging to factor directly.

Strategies for Factoring

  1. Expansion and Grouping:

    • Expand the expression to obtain a standard polynomial form.
    • Attempt to group terms and factor by grouping. However, this approach can be quite tedious and may not lead to a successful factorization.
  2. Substitution:

    • Consider a substitution to simplify the expression.
    • Let y = (x+5).
    • The expression becomes (y-4)(y+4)y^2 + 63, which simplifies to y^4 - 16y^2 + 63.
    • This new expression is a quadratic in y^2. We can factor it as (y^2 - 7)(y^2 - 9).
    • Substitute back y = (x+5) to get ((x+5)^2 - 7)((x+5)^2 - 9).
  3. Recognizing Patterns:

    • Observe that the expression resembles the expansion of a perfect square.
    • Notice that ((x+5)^2 - 7)((x+5)^2 - 9) can be rewritten as ((x+5)^2 - 8)^2 - 1.
    • This pattern allows us to factor the expression further using the difference of squares formula: (a^2 - b^2) = (a+b)(a-b).
    • The final factored expression becomes ((x+5)^2 - 8 + 1)((x+5)^2 - 8 - 1), which simplifies to ((x+5)^2 - 7)((x+5)^2 - 9).

Solving the Equation

To find the roots (solutions) of the expression, we set it equal to zero:

((x+5)^2 - 7)((x+5)^2 - 9) = 0

This equation is satisfied when either factor equals zero:

  • (x+5)^2 - 7 = 0
  • (x+5)^2 - 9 = 0

Solving for x in each case:

  • (x+5)^2 = 7

  • x + 5 = ±√7

  • x = -5 ±√7

  • (x+5)^2 = 9

  • x + 5 = ±√9

  • x = -5 ±3

Therefore, the solutions to the equation are:

  • x = -5 + √7
  • x = -5 - √7
  • x = -2
  • x = -8

Conclusion

Factoring and solving the expression (x+1)(x+9)(x+5)^2 + 63 involves recognizing patterns, using substitution, and applying factoring techniques. The solutions, or roots, of the equation are x = -5 + √7, x = -5 - √7, x = -2, and x = -8. This demonstrates the power of algebraic manipulations and pattern recognition in simplifying complex expressions.

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