I am coming from zero math and making this made me so thankful. Please continue teaching with real life examples.

@ontendo great job, I might have missed this.

I was just curious how did you evaluate the equation for

b = (-p -q) * a

c = -p * -q * a

I am trying to wrap my head around it

I don’t remember quite clearly because I gave names depending on the video. I have to watch the video again for that. I was just doing how this c or b can be found from other values like what is the relation.

formulae of parabola

Standard: y = ax^2 + bx + c

Interception: y = a(x-p)(x-q)

Vertex: y = a(x-h)^2+ k OR x = a(y-k)^2+h

I am not sure how you substituted or came up with

b = (-p -q) * a

c = -p * -q * a

When ever you remember do share it, It would be a great help

thank you. ;-D

Hey Splunky,

I can give you the answer.

You can deduct those formulas from y = a(x-p)(x-q).

When you go back to the standard formula you do the following steps using FOIL method:

y = a(x^2- qx - px - p * - q)

y = ax^2 -aqx -apx + a(-p*-q)

then you can say, because x is a common factor in -aqx -apx

y = ax^2 + x(-aq - ap) + a(-p * -q)

If you pay attention to this, you can notice that (-aq - ap) is just a number and we can call this *b* and a(-p* -q) is also a number you can call this *c*.

Going back to your question we can say that:

b = (-aq - ap)

a is a common factor then you end with

b = a * (-q -p)

And

c = a (-p * -q)

I hope I was clear, if you have any other questions don’t hesitate to ask.