This week, we made reference to the questions in the past year exam papers (of other schools) for our revision practices.
On Friday, we started revision on Algebra and discussed questions that are not found in these papers.
Below is the complete solution that we had discussed during our lesson on 29 Sep (Friday). Do take note of the presentation of the working.
As mentioned in class, this was a higher order thinking question because I had removed the 'scaffolds' (i.e. smaller parts leading to the final answer).
However, to tackle such question, always link to what you are already familiar with, then apply them - along the way, you will find yourself working on something similar to the required form.
While this is pitched as a S2 question, you can apply knowledge and skills in Mensuration (area of circle and square) and Algebra (forming equation, factorisation, re-organising the terms), and basic reasoning to solve the problem.
These questions merely help us to recall the basics of algebra.
We need to be cautious of the substitution
Manage the 3 terms like you are managing numerical fractions!
Find the common denominator, and do not forget the brackets when 'combining' the terms.
3rd question: Remember that ratio can be expressed as a fraction.
Note that it's always good to find x/y term before finding what is required.
Mentioned in class, there's more than one way to do (i).
I've presented 3 ways below how to show LHS of equation = RHS of equation.
We also spoke about NOT using any numbers to do the "shown" question.
Remember that "hence" means make use of what is given in (i) to do (ii)
Last, but not least, we discussed this question that requires us to solve the unknowns by comparing terms