Grade six, Edexcel GCSE Maths

Revision Notes

Why do we want to know about straight lines and their equations?

Straight Line Graphs (Linear Graphs) have lots of uses in mathematics – one use is in navigation.  We may want to know the equation of a straight line so we can program it into a computer that will plot the line on a screen, along with several others, to make shapes and graphics.

How do we find the equation of a straight line?

  1. The general EQUATION of a straight line is y = mx + c where
    • m is the gradient
    • c  is the y-axis intercept 
  2. To find the EQUATION of a straight line you need TWO things:
    • the gradient, m
    • any point on the line
  3. You might find these things from a graph, another equation or two points
  4. You may be asked to give the equation in the form ax + by + c = 0
    (especially if m is a fraction)
    If in doubt, SKETCH IT!

Example

Straight Lines - Finding Equations Example 1, IGCSE & GCSE Maths revision notes

Sketch Parallel Lines, IGCSE & GCSE Maths revision notes

Straight Lines - Finding Equations Example 2, IGCSE & GCSE Maths revision notes

Question

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Edexcel GCSE Maths Notes

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After 24 years teaching A Level Further Maths, Maths whizz Simon focused his attention on tutoring. He’s helped thousands of young people make sense of Maths and now he’s helping you too – aren’t you lucky! He’s even worked as an Edexcel examiner, so knows exactly what they’re looking for.