# E-Maths Note : Algebraic Expansion

This is a topic some of which is learnt ever since Primary 6.

Through my years of coaching, I notice quite a handful of students form blocks when they dealt with this topic that starts with "A" and ends with "a".

Haha! Yes! It's Alegbra! I was introduced of this thing in Primary 6. It was the ONLY method my dad taught me to solve word problems then. I didn't understand what he was telling me.... totally huh? huh? huh?

Well, I am glad I figure out the x-es & y-es eventually. Many students tend to see algebra to be abstract. In fact, it can be explained in terms of apples, oranges, pears .... ( This is my ONLY drawing subject- basic fruits) Those who have the "good fortune" will know the level of drawing :-)

Now I am going to share a few tips to make your learning of Algebra Expansion easier and simpler. One of the very powerful yet always underestimated strategies is the correct usage of brackets. Yes! Brackets are big deal okie!

3 golden algebra rules :

• $(A+B)^2 = (A)^2 +2(A)(B)+(B)^2$
• $(A-B)^2 = (A)^2 -2(A)(B)+(B)^2$
• $(A+B)(A-B)= (A)^2 -(B)^2$
• These 3 golden rules when applied correctly will definitely make your life easier. Now I'm going to share with you some common errors that students commit when they underestimate the importance of brackets

Qn: Expand $(3x+2y)^2$
Ans : $(3x+2y)^2= 3x^2+12xy+2y^2$ --> this is not right
Correct Ans : $(3x+2y)^2= (3x)^2+12xy+(2y)^2 = 9x^2+12xy+4y^2$

I hope this is a useful tip for you :)

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### Ai Ling Ong

Hi, I'm Ai Ling Ong. I enjoy coaching students who have challenges with understanding and scoring in 'O' Level A-Maths and E-Maths. I develop Math strategies, sometimes ridiculous ideas to help students in understanding abstract concepts the fast and memorable way. I write this blog to share with you the stuff I teach in my class, the common mistakes my students made, the 'way' to think, analyze... If you have found this blog post useful, please share it with your friends. I will really appreciate it! :)