Booster C 3.26b - Equations (2)

Learning Objective:

  • we are learning to:
    • create and solve linear equations to solve shape problems
    • to solve cubic and other equations by trial and improvement methods

Worked Solutions to Booster C Ex 3.26b:


  • This topic is useful because these are common D & C grade GCSE exam questions
  • In a typical year these skills are worth about ### out of 200 of the available marks at GCSE higher tier
  • This skill leads to plotting graphs of functions such as in Booster C

  • After your GCSE you might expect to use this to solve problems that arise in sciences (especially physics and chemistry) at AS/A-level
    • This topic could help you if you want to work in engineering, electronics, economics and other areas where complicated equations need a practical, accurate but not exact answer.


  • Before you start it would help to know how to solve simple linear equations and you can substitute into formulas including cubing and squaring;
  • You will have a deeper understanding if you also are fluent with negative numbers and have a robust understanding of place value


  • The best method(s) for questions such as these is...
  • cubic by trial and improvement question.docx
  • cubic by trial and improvement answer.png
  • Watch out for...The desired solution is an organised search for a value which is the closest value (to the required degree of precision, e.g. 1 decimal place) to the exact solution. Marks would often be missed or denied if the method is omitted.
  • In the exam you can check your answer by...


  • Here are some examples of people getting questions on this topic right:
  • Here are some examples of people getting questions on this topic wrong in typical ways:


  • Some more mixed examples:


  • One of the most effective ways to revise is to teach someone else.
  • How would you explain this topic to a friend?
  • Make a revision card or poster showing the key points and illustrate it with examples.
  • Write a 'fake exam question' to assess this topic and write a mark scheme to mark it. Test your question out on another learner. Can you make your question and mark scheme so realistic that you can fool your maths teacher?


  • Check you've mastered this skill by trying these adapted GCSE past-paper questions:


  • Next try learning...

last edited: May 1, 2013 12:33 am