Factorising any quadratic formula. + some thoughts

Melody:

I just stumbled on this you tube clip.
I thought it was quite good. That is because it is basically the way I teach it (I have looked at many methods in the past and i like this one)
My only criticism of this clip is that he keeps waving his pen about and it is a distraction.
http://www.youtube.com/watch?v=ZQ-NRsWhOGI
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I was thinking that we could start a thread, where the url's of the resources that we like, are added.
Maybe they could be posted individually when first introduced but then assigned to a thread bank of resources.
Does this sound like something people would want to do?
Or is it easier just to go find them each time on the web?
Obviously there are a lot of resources out there. Some are good, some are really not.
also, we won't all like the same ones.

I am just looking for some comments/ideas please.
Would anyone, other than me, like to organize something like this. If not, it doesn't matter. I know you are all busy people.
We could even have our own post within the thread that we look after with edits and additions for ourselves. Do you understand what i mean?
Thanks,
Melody.

I think it is a good idea to have a thread where everyone can share his or her recources.
I'd use it to give quicker answers to the similar questions that are asked every day.
People might share recources which are not so useful (could be a man waving a pen through the screen (just kidding )) but we're not obliged to use them in our answers.
Simply watch the recource before your use it in an answer and then it will probably be an excellent idea!
How about this thread?

I want to organise this better but I need to use this now so I am just going to put it here.

140205 Elimination method LaTex.JPG

Again, I am not intending to leave this here for ever I just wanted to use it again today.

Positive and negative numbers

For multiply and divide it is very simple. If the signs are the same then the answer is positive. If the signs are different the answer is negative. See, simple.

For addition and subtraction it is a bit trickier.
I am a big user of number lines. Until you get used to it you should actually draw your number lines. I am assuming that you know how to do that.
Zero in the middle, positive numbers going off to the right, negative numbers going off to the left.

Say it is 1+6. You start at 1 then go 6 places in the positive direction and you get 7 (yea, I know, you already knew that)
Now -3+8 Start at -3 and go 8 in the positive direction and what do you get?
Now 4 - 9 start at 4 and go 9 in the negative direction and what do you get?
Now -2- 8 start at -2 and go 8 in the negative direction and what do you get?

When you get good at it you can stop drawing the number line but you should still imagine it. If you use a note book, imagine 0 in the crease of the book, the positive numbers will be on the right and the negative numbers on the left.

Now, what about those pesky + - things
for starters, If you see something like 7+(-8) it is exactly the same as 7+ - 8 (You can put the bracket in or take it away - it doesn't matter.)
That goes for 3 - - 6 = 3- (-6) as well.

Now think of a thermometer. 0 degrees is in the middle. The positive numbers are hot numbers. The negative or minus numbers are cold numbers.
Let's think about 4+ + 5 you are adding heat so it must get hotter. So it is 4+5
What about 6+-7 This time you are adding cold. So it has to get colder. It must be 6-7
And 8 - + 3. This time you are taking away heat so it has got to get colder. It must be 8-3
and lastly -1 - - 4. This time you are taking away coldness so it has to get warmer. It must be -1+4

With pluses and minuses you can also think of it like this.
If two signs are so close together that you can put a circle around them without anything getting in the way then,
if the signs are the same you replace them with a positive.
if the signs are different you replace them with a negative.

am going to give you some questions to answer now.

1) Now -3+8 Start at -3 and go 8 in the positive direction and what do you get?
2) Now 4 - 9 start at 4 and go 9 in the negative direction and what do you get?
3) Now -2- 8 start at -2 and go 8 in the negative direction and what do you get?
4) 0-8=
5) -2-+6=
6) 1-4+(-7)=
7) -9++4 =
8) 13+(-5)=
9) -4 x 6 =
10) 3 x -6 =
11) -5 x -3=
12) 20 / -4=
13) -8 / 2=
14) -15 / -5=
15) +4 x +7=

This is a logarithm page that I constantly refer people to.
http://en.wikipedia.org/wiki/List_of_logarithmic_identities

Hey, found something - but by chance as I think the thread title is lacking insight into content. A thanks is in order to melody for the post on sign value and number line..

Yes Stu you're right. There is just a scramble of ideas in here. This forum is very new. If you read through some of the 'end of day wrap up' posts you might get a better feel for what is happening in here. you can skip the credits, But i usually have something to say besides the credits each day.
Until 'I like Serena' arrived, on the 24th January, it was just me and the young people in this forum.
I had done very little foruming prior to this so if you find some of the setup in here bizarre. You are probably correct.
You've actually given me some good ideas. Why don't you read my nightly posts and become an integral part of our community?
Melody.

Melody:

Yes Stu you're right. There is just a scramble of ideas in here. This forum is very new. If you read through some of the 'end of day wrap up' posts you might get a better feel for what is happening in here. you can skip the credits, But i usually have something to say besides the credits each day.
Until 'I like Serena' arrived, on the 24th January, it was just me and the young people in this forum.
I had done very little foruming prior to this so if you find some of the setup in here bizarre. You are probably correct.
You've actually given me some good ideas. Why don't you read my nightly posts and become an integral part of our community?
Melody.

I liked what you did there with the number line Melody,
pretty sure that I might use that pretty soon

Since I don't know where to put them yet I thought I'd drop these two recources for percentages right here.

http://www.mathsisfun.com/definitions/percent.html
http://www.mathsisfun.com/percentage.html

They are pretty self explainatory

bump

Melody:

Yes Stu you're right. There is just a scramble of ideas in here. This forum is very new. If you read through some of the 'end of day wrap up' posts you might get a better feel for what is happening in here. you can skip the credits, But i usually have something to say besides the credits each day.
Until 'I like Serena' arrived, on the 24th January, it was just me and the young people in this forum.
I had done very little foruming prior to this so if you find some of the setup in here bizarre. You are probably correct.
You've actually given me some good ideas. Why don't you read my nightly posts and become an integral part of our community?
Melody.

Hey great job and lots stopping by. I would only suggest as I have done to a friend beginning a forum to look at some bigger sites ie twoplustwo etc and see how they segment it up into categories with must read stickies. I know people are in a rush to ask questions in general, but if their question was answerd 2 posts ago then they would be able to see it, in x forum with xn title. googluck. I'l be around and the more silly I sound now with my questions the less sillly i sound later, ideally haha but it's also such a large subject to learn and I'm not on to anything physics yet. But good job and I've also been reading the end of day post since I came. And I'm sure the effort is appreciated by all as time is given generously in answering the many posts..

I really do want to get to this.
Just not enough hours in a day.