Solution of a Quadratic Equation by Factorisation

4.3 Solution of a Quadratic Equation by Factorisation

Description

Quick Overview

This section covers the process of solving quadratic equations through factorization, including examples and methods to identify roots.

Standard

In this section, students learn how to find the roots of quadratic equations using factorization, exploring various examples and the mathematical reasoning behind identifying solutions that satisfy the quadratic equation.

Detailed

In Chapter 4.3, students explore the solution of quadratic equations through factorization. A quadratic equation generally takes the form ax² + bx + c = 0, with a non-zero coefficient a. To find roots, students learn that any real number α is a root if substituting it into the equation satisfies it (i.e., it results in zero). The process of factorization is emphasized as a method to break down the quadratic polynomial into simpler linear factors. The section includes illustrative examples, such as finding the roots of the equations 2x² - 5x + 3 = 0 and 6x² - x - 2 = 0, demonstrating the splitting of the middle term and the significance of equating factors to zero to find the solutions. Further emphasis is placed on representing real-world problems as quadratic equations, reinforcing the practical applications of the concepts learned.

Key Concepts

  • Roots of Quadratic Equations: Values that satisfy the equation.

  • Factorization Method: Splitting the middle term to find roots.

  • Real-world Applications: Quadratic problems represented mathematically.

  • Discriminant: A tool to determine the type of roots.

Memory Aids

🎵 Rhymes Time

  • Quadratics are neat, roots we must find, factor them fast, and use your mind!

📖 Fascinating Stories

  • Once upon a time, there were two friends called Roots and Factor who went on an adventure to solve equations, unlocking secrets with every factor they found.

🧠 Other Memory Gems

  • To remember the quadratic formula: 'A-B-C, Over A's two, gives us the roots we pursue!'

🎯 Super Acronyms

R.F.D. - Roots, Factorization, and Discriminant; key concepts in quadratics!

Examples

  • Finding the roots of 2x² - 5x + 3 = 0 by factorization.

  • Solving 6x² - x - 2 = 0 using the factorization method.

Glossary of Terms

  • Term: Quadratic Equation

    Definition:

    An equation of the form ax² + bx + c = 0, where a, b, and c are constants, and a is not zero.

  • Term: Roots

    Definition:

    The values of x that satisfy a quadratic equation, making it equal to zero.

  • Term: Factorization

    Definition:

    The process of breaking down an expression into simpler products, specifically into linear factors in the case of quadratic equations.

  • Term: Zeroes of a Polynomial

    Definition:

    The x-values that make the polynomial equal to zero.

  • Term: Discriminant

    Definition:

    The expression b² - 4ac that determines the nature of the roots of a quadratic equation.

Example Find the roots of the quadratic equation 8x^{2} - 4x - 16 = 0.

Solution

We have
\[ 5x^{2} + 3x + 2 = 0 \]
Using the quadratic formula,
\[ x = \frac{-b \pm \sqrt{b^{2} - 4ac}}{2a} \]
where,
- a = 5
- b = 3
- c = 2
Substituting the values,
\[ x = \frac{-3 \pm \sqrt{3^{2} - 4 \cdot 5 \cdot 2}}{2 \cdot 5} \]
This simplifies to
\[ x = \frac{-3 \pm \sqrt{9 - 40}}{10} \]
Indicating that the roots of the equation 5x^{2} + 3x + 2 = 0 will reveal complex solutions.
We can verify the nature of the roots through the discriminant.


Example Find the roots of the quadratic equation 5x^{2} + 3x + 2 = 0.