Edexcel IGCSE Maths

Revision Notes

2.16.1 Solving Inequalities - Linear

What is a linear inequality?

  • An Inequality tells you that one expression is greater than (“>”) or less than (“<”) another
    • “⩾” means “greater than or equal to”
    • “⩽” means “less than or equal to”
  • A Linear Inequality just has an x (and/or a y) etc in it and no x2 or similar
  • For example, 3x + 4 ⩾ 7 would be read “3x + 4 is greater than or equal to 7”

Solving linear inequalities

  • Solving linear inequalities is just like Solving Linear Equations (so review these notes first)
  • You also need to know how to use Number Lines and deal with “Double” Inequalities

1. Same rules as solving equations: GROF GROBLET FIND ANSWER!
But do NOT multiply (or divide) by negative numbers
2. When drawing NUMBER LINES:

Solving Inequalities - Linear RN1, downloadable IGCSE & GCSE Maths revision notes

3. For “double” inequalities just do the same thing to all three parts

Worked Example

Number-Line--2-to-1, IGCSE & GCSE Maths revision notes

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