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How to Evaluate an Algebraic Expression by Substitution
In the following maths activities I will explain to you how to evaluate algebraic expressions by substitution. I will teach you all you need to know about evaluating expression to pass your IGCSE GCSE Maths exam. I will also show you in the videos the commonly made mistakes by students and the questions you should be asking yourself. Substitution with algebra is the same as with football. You replace one player (letter) with anew one (a number). Could you answer the following question already? Evaluate x^2 + 3x  2 for x = 2. If you study the maths videos during your maths revision you will be able to answer this question. Is your answer 12? Well then you (together with many of your peers) do not know how to use a calculator (you are wrong)!!! The correct answer is 4. Check the videos and learn how to evaluate expressions by substitution.
