Simple Inequalities (Linear and Quadratic)

Simple Inequalities (Linear and Quadratic)

Overview

  • Inequalities represent a relationship between quantities, stating that one is greater than, less than, or equal to another.
  • Simple inequalities are part of the wider spectrum of inequalities and include linear and quadratic inequalities.

Linear Inequalities

  • A linear inequality looks much like a linear equation, but with an inequality sign instead of an equals sign.
  • Linear inequalities can be solved in a similar way to linear equations.
  • Examples of linear inequalities include x + 3 > 7 or 2y - 4 ≤ 8.

Quadratic Inequalities

  • Quadratic inequalities are inequalities that involve a quadratic expression, such as x^2 + 3x - 10 > 0.
  • The graph of a quadratic inequality is a parabola which can be useful in understanding and solving quadratic inequalities.

Solving Simple Inequalities

  • To solve a simple inequality, the aim is to isolate the variable.
  • Basic operations such as adding, subtracting, multiplying, and dividing can be performed on both sides of an inequality, much like in an equation.
  • When multiplying or dividing by a negative number, the direction of the inequality sign must be reversed.
  • For quadratic inequalities, solutions are often found by first solving the corresponding quadratic equation, and then deciding on the appropriate range for the variable.

Applying Inequalities

  • Inequalities can be used to represent various real-world situations where there is a range of possible solutions.
  • For example, inequalities can be used to model situations involving budgets, limits, or any situation where there may be a minimum or maximum limit.

Common Pitfalls

  • Always remember to flip the inequality sign when multiplying or dividing by negative numbers.
  • When solving quadratic inequalities, remember that the solution may be a range of values, not a specific value.
  • Avoid ambiguity by always using clear notation, especially when dealing with compound inequalities.

Practise Problems

  • Try out numerous problems involving linear and quadratic inequalities to hone your skills.
  • Problems should include both algebraic and word problems to provide a wide range of practice.
  • Solving inequalities should involve performing operations correctly, using clear notation, and correctly interpreting inequality statements. Be assured that practice in this area will build a solid foundation in understanding and solving inequalities.