[Challenging Question] #9 Application of Factorisation

A handout comprisilng the following questions was given in class.

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[UPDATE on 7 July] Solution received 

From Irina

• Very clear and systematic presentation of working. 👍
• Approach: Substitution is cleverly used to make the working easy to read and simplify 👍
• Answers are correct. 👍

[Point to ponder] Instead of using x = 6987650, what if we use x = 6987654? 

Try that to see how the expression would look like now.

[To improve] Use descriptive word like "Let x = 6987650" instead of using a straight line, which could be mistaken as "minus"

From Ruihao

• Very clear and systematic presentation of working. 👍
• In Ruihao's working, you would notice that he exercised his 'eye power' and notice he could applied special product to factorise part of the expression (in the course of simplifying the expression 👍
• Answers are correct 👍