Summary
Equations and inequalities involve solving for unknown values using algebraic methods and graphical interpretations. This topic covers linear and quadratic equations and inequalities, including their solutions and graphical representations.
- Linear simultaneous equations — a system of two or more linear equations solved together to find a common solution. Example: x + 3y = 11 and 4x - 5y = 10 solved to x = 5, y = 2.
- Quadratic simultaneous equations — a system involving one linear and one quadratic equation solved together. Example: y - x = 5 and y = x² + 3x + 2 solved to x = -3 or x = 1.
- Linear inequalities — expressions showing the relationship of inequality between two expressions. Example: x < 4 represented on a number line.
- Quadratic inequalities — inequalities involving quadratic expressions, often solved by graphing. Example: 2x² + 5x + 3 ≥ 1.
- Regions — areas on a graph that satisfy a set of inequalities. Example: y < f(x) represents points below the curve y = f(x).
Exam Tips
Key Definitions to Remember
- Linear simultaneous equations
- Quadratic simultaneous equations
- Linear inequalities
- Quadratic inequalities
Common Confusions
- Mixing up the methods for solving linear and quadratic equations
- Forgetting to use solid or dashed lines for inequalities on graphs
Typical Exam Questions
- Solve the simultaneous equations x + 3y = 11 and 4x - 5y = 10? x = 5, y = 2
- Find the set of values of x for which 5x − 3 ≤ 2x + 18? x ≤ 7
- Solve the inequality x² - x - 2 > 0? x < -1 or x > 2
What Examiners Usually Test
- Ability to solve and interpret simultaneous equations
- Understanding of graphical representation of inequalities
- Correct application of solving methods for different types of equations