Study Notes
Quadratic equations are algebraic expressions that can be solved to find two different solutions.
- Quadratic Equation — an equation of the form ax^2 + bx + c = 0. Example: x^2 - x - 6 = 0
- Factorisation — a method to solve quadratic equations by expressing them as a product of two binomials. Example: (x-3)(x+2)=0
- Algebraic Manipulation — a method involving rearranging and simplifying the equation to find solutions. Example: 16x^2 - 9 = 0 becomes (4x+3)(4x-3)=0
- Quadratic Formula — a formula used to solve quadratic equations when factorisation is not possible. Example: For ax^2 + bx + c = 0, use the formula to find solutions.
Exam Tips
Key Definitions to Remember
- Quadratic Equation: ax^2 + bx + c = 0
- Factorisation: Expressing a quadratic as a product of binomials
- Quadratic Formula: A formula to find solutions when factorisation is not possible
Common Confusions
- Forgetting to find both solutions (positive and negative)
- Using square roots on negative numbers
Typical Exam Questions
- Solve x^2 - x - 6 = 0 by factorisation? x = 3 or x = -2
- Solve 16x^2 - 9 = 0 by algebraic manipulation? x = 3/4 or x = -3/4
- How fast did Doug drive to the conference? Use quadratic equations to solve
What Examiners Usually Test
- Ability to factorise quadratic equations correctly
- Correct application of the quadratic formula
- Understanding of when to use each method