Conquering the Quadratic Equation: A Step-by-Step Guide to Solving 4x² – 5x – 12 = 0

4x ^ 2 - 5x - 12 = 0

quadratic equations are a fundamental concept in algebra, forming the foundation for solving countless problems across various mathematical disciplines. One particular quadratic equation that frequently arises is 4x² – 5x – 12 = 0. This article equips you with the necessary tools and a step-by-step approach to unravel its mysteries and arrive at the solutions.

Unveiling the Structure: Understanding the Quadratic Equation

A quadratic equation is characterized by the general form ax² + bx + c = 0, where a, b, and c are constants, and a ≠ 0. In the equation 4x² – 5x – 12 = 0, we can identify the following:

  • a (coefficient of the x² term): 4
  • b (coefficient of the x term): -5
  • c (constant term): -12

The objective is to manipulate the equation algebraically to isolate x, the variable, and arrive at the values that satisfy the equation.

Strategic Approaches: Factoring and the Quadratic Formula

There are two primary methods for solving quadratic equations: factoring and the quadratic formula. We will explore both approaches to provide a comprehensive understanding.

1. Factoring: Dismantling the Equation

Factoring involves restructuring the equation by finding two expressions that, when multiplied together, yield the original equation. In essence, we are decomposing the expression on the left side of the equation (4x² – 5x – 12) into its constituent parts.

For the equation 4x² – 5x – 12 = 0, factoring entails finding two binomials (expressions containing x and a constant term) that satisfy the following conditions:

  • The product of the leading coefficients (the numbers multiplying the highest power of x in each binomial) is equal to 4 (coefficient of x² in the original equation).
  • The sum of the products of their coefficients is equal to -5 (coefficient of the x term in the original equation).
  • The constant terms of the two binomials multiply to give -12 (constant term in the original equation).

Through trial and error or a systematic approach, we discover that the equation can be factored as:

(4x + 3)(x – 4) = 0

This signifies that either (4x + 3) = 0 or (x – 4) = 0.

2. The Quadratic Formula: A Universal Solution

The quadratic formula offers a universal method to solve any quadratic equation. It is expressed as:

x = (-b ± √(b² – 4ac)) / 2a

where a, b, and c are the coefficients from the general quadratic equation form (ax² + bx + c = 0).

In our case, substituting the values from the equation 4x² – 5x – 12 = 0:

a = 4, b = -5, c = -12

Applying the formula:

x = (-(-5) ± √((-5)² – 4 * 4 * -12)) / (2 * 4)

x = (5 ± √(217)) / 8

Since the square root of 217 is an irrational number (a number that cannot be expressed as a simple fraction), we have two solutions:

x₁ = (5 + √217) / 8 x₂ = (5 – √217) / 8

These solutions correspond to the values of x that make the original equation true.

Interpreting the Solutions: What Do the Answers Mean?

The solutions we obtained, x₁ = (5 + √217) / 8 and x₂ = (5 – √217) / 8, represent the values of x that satisfy the equation 4x² – 5x – 12 = 0. When we substitute either x₁ or x₂ back into the original equation, both sides will evaluate to zero, confirming their validity.

These solutions depict the x-intercepts of the graph of the equation 4x² – 5x – 12 = 0. The x-intercept is the point where the graph intersects the x-axis, signifying the values of x for which the function outputs zero.

Mastery in Action: Applying the Solutions to Real-World Scenarios

While the solutions we derived hold true mathematically, their practical applications depend on the context in which the equation arises. Quadratic equations find relevance in various domains, including:

  • Projectile Motion: Quadratic equations can model the trajectory of a projectile, where factors like initial velocity and launch angle influence the path described by a quadratic equation. By solving for the time it takes the projectile to reach a certain height or distance, we can optimize launch parameters or predict outcomes.
  • Circuit Analysis: In electrical circuits, quadratic equations govern the relationship between voltage, current, and resistance. Solving these equations allows us to determine unknown components’ values or predict circuit behavior under specific conditions.

  • Optimization Problems: Quadratic equations play a crucial role in optimizing quantities. For instance, maximizing profit or minimizing cost in business scenarios often translates to solving quadratic equations to identify the optimal values of variables.

Understanding how to solve quadratic equations like 4x² – 5x – 12 = 0 equips you with a foundational tool for tackling more complex problems across various disciplines.

Beyond the Basics: Exploring Advanced Concepts

This article has focused on solving a quadratic equation using factoring and the quadratic formula. As you delve deeper into mathematics, you will encounter more advanced concepts related to quadratic equations, such as:

  • The Discriminant: The part of the quadratic formula under the radical (b² – 4ac) is known as the discriminant. Its value determines the nature of the solutions:

    • A positive discriminant indicates two distinct real number solutions.
    • A zero discriminant signifies a repeated real number solution (one solution with a multiplicity of two).
    • A negative discriminant implies two complex solutions (solutions involving the imaginary unit √-1).
  • The Complex Plane: When the discriminant is negative, the solutions involve complex numbers. The complex plane is a visual representation of complex numbers, aiding in understanding their properties and operations.

  • The Quadratic Formula for Higher-Order Polynomials: While the quadratic formula applies specifically to quadratic equations, there are analogous formulas for solving higher-order polynomial equations. These formulas become progressively more complex as the degree of the polynomial increases.

By grasping these advanced concepts, you will gain a deeper comprehension of quadratic equations and their applications in various mathematical domains.

Conclusion: Demystifying the Quadratic Equation

The seemingly intimidating equation 4x² – 5x – 12 = 0 can be effectively tackled using factoring or the quadratic formula. This article has equipped you with the tools and knowledge to solve this specific equation and understand the broader concepts of quadratic equations. Remember, practice is key to mastering these techniques. As you encounter more complex quadratic equations, apply the methods outlined here and explore advanced concepts to solidify your understanding.

With dedication and a thirst for knowledge, you will conquer the world of quadratic equations and unlock their potential in solving problems across various disciplines.

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