Lesson Plan: Factorisation of Quadratic Expressions
Duration: 30 minutes
Subject: Mathematics
Year Group: 10
Lesson Objectives
By the end of this lesson, students will be able to:
- Understand the concept of quadratic expressions.
- Identify and use the methods of factorisation specific to quadratic expressions.
- Apply these methods to factorise quadratic expressions effectively.
Required Materials
- Whiteboard and markers
- Worksheets with quadratic expressions for practice
- Graphing calculators (optional)
- Projector (for visual aids)
Lesson Outline
Introduction (5 minutes)
- Begin with a brief recap of what a quadratic expression is, highlighting the standard form ( ax^2 + bx + c ).
- Explain that the focus of today's lesson is factorisation—transforming the quadratic expression into the product of two binomials.
Direct Instruction (10 minutes)
-
Identify Coefficients:
- Define ( a ), ( b ), and ( c ) in the context of a quadratic expression.
- Example: For ( 2x^2 + 7x + 3 ), identify ( a = 2 ), ( b = 7 ), ( c = 3 ).
-
Methods of Factorisation:
- Method 1: Factor by Inspection: When the quadratic can be easily split into two factors by examining the product and sum of coefficients.
- Method 2: Using the Quadratic Formula: State that though primarily used for finding roots, it can assist in factorisation.
-
Step-by-Step Factorisation:
- Show how to factorise ( x^2 + 5x + 6 ) by finding two numbers that multiply to ( 6 ) (the constant term) and add up to ( 5 ) (the coefficient of ( x )).
- Result: ( (x + 2)(x + 3) ).
Guided Practice (10 minutes)
- Distribute worksheets containing a variety of quadratic expressions for students to practise factorisation.
- Work through the first example together, then allow students to work in pairs on the next few problems, providing support as needed.
Independent Practice (5 minutes)
- Students complete the remaining questions on their own, aiming to solve at least three expressions by factorisation.
Homework Assignment
Tasks:
-
Factorise the following quadratic expressions:
- a) ( x^2 + 8x + 15 )
- b) ( 3x^2 - 9x )
- c) ( x^2 - 4x - 12 )
-
Create your own quadratic expression and factorise it.
Correct Answers:
- a) ( (x + 3)(x + 5) )
b) ( 3x(x - 3) )
c) ( (x - 6)(x + 2) )
Conclusion (2 minutes)
- Review key concepts covered in the lesson.
- Encourage students to reflect on how factorisation simplifies quadratic expressions and helps in solving equations.
By adhering to this lesson plan, students will build a solid understanding of factorising quadratic expressions, leading to improved confidence in their mathematical abilities.