T1W7 - 3E2 (Symmetrical Properties of Roots of an Eqn)

When I started this topic, I used the whole of one period to show pupils how to obtain the results: given x^2 + (b/a)x + (c/a) = 0, sum of roots = alpha + beta = -b/a & product of roots = alpha * beta = c/a. As the proof was rather abstract, majority of the pupils in the class were lost as they could not understand the proof at all.

Hence, the following lesson I tried a different approach. I created a worksheet that required pupils to discover general forms for sum of roots & product of roots with 4 different quadratic eqns. For this lesson, pupils dealt with numbers instead of a, b and c. After completing the worksheet, all of them were able to write down the sum of roots and product of roots given any quadratic eqns. I did not even need to explain to them why the reason for the ‘minus’ sign in as they deduced the formula on their own. I was really happy that this method worked for them. Thus, I was able to carry on the lesson on deriving another eqn using the sum of roots & product of roots from the first eqn.