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Maths...help !

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:D

 

Ok, look at this...

 

 

4x^2 - 8x + 3 <<<< Factorise

 

Note : (4x^2 is four x squared)

 

Ok, can anyone explain how to do it, STEP by step....ESPECIALLY the last 3 steps....much appreciated !

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PropellerAds

:D

 

using factorin?

 

2 ways: first way, is "guess and check". The other i don't know what it is called.

 

Will start with the way that is nameless :D

 

You take the first and last numbers and you multiply them: that gives you 4 X 3 --> which is 12.

 

Now there are two factors of 12, that when added give you the middle number you have written: 8.

 

Which 2?

 

obviously, 6 and 2. Cause 6 + 2 gives you 8. BUt you need it to be -8. So the signs should be negative. -6 + -2 = -8.

 

Now rewrite the equation as:

 

4X^2 - 2x - 6X+ 3

 

now do GCF: greatest common factor:

 

Do it as 4X^2 - 2x together and -6X+ 3 together:

 

You get: 2x(2x-1) -3(2x-1)

 

^Now what's inside the two brackets is the same, so you know you did it right.

 

You take the numbers outside each bracket and make one bracket:

(2x- 3) (2x -1).

 

:D

 

The other way, gues and check, you just open 2 brackets nd keep guessing: :D :D

 

(2x - _______) (2x+ _________)

then you multiply the right of the first bracket with the left of the first bracket, then the left of the first bracket with the right of the second and add them up: see if you get the right middle.

 

^:D

I can't explain math online :D

 

good luck!

 

:D

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now do GCF: greatest common factor:

 

Do it as 4X^2 - 2x together and -6X+ 3 together:

 

You get: 2x(2x-1) -3(2x-1)

 

^Now what's inside the two brackets is the same, so you know you did it right.

 

:D

 

Wait wait wait wait, What did you do here...in the quote....i have no idea how you made it to 2x(2x-1) etc etc......where did you get that from?

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can i interfere ?

 

4X^2 can be written as 2X x 2X [product]

 

n so 4X^2 - 2x can be written as :

2x(2x-1) taking 2X common from each.

 

similarly for the next : -6X+ 3

 

taking -3 common,

-3(2x-1)

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:D

 

^ OH!! Sorry, i assumed you would have taken that: basically this is short for greatest common factor:

 

So for example if i tell you factor 18X + 36 what you do is find "the common thing".

 

Let's try that one! what is common between those "numbers"? WEll! 36 is 18 X 2 right? So you take 18 -or the common number- outside and you open brackets:

 

18 ( ______________)

 

 

Now go back to what it said: 18 X + 36 and divide each number by the 18 that is outside:

 

so you have 18 (x + 2)

 

??

 

 

if i were to write it out in a long way it would say this:

 

18 (18x divided by 18, + 36 divided by 18)

that gives you 18 (x + 2)

 

okay? or still weird?

 

so basically you apply the same thing to the problem you gave us.

 

REmember, we rewrote the quadratic formula as:

 

4X^2 - 2x - 6X+ 3

 

put together the 4x^2 and 2x in one bracket *if you want* and the other numbers in a different bracket:

 

(4X^2 - 2x) - (6X+ 3)

 

now, what is common between 4x ^2 and 2x?

 

2x right? So you take 2x outside of the bracket and then divide the rest by the outside thing.

 

2x (2x -1)

 

do the same thing with the -(6X+ 3)

 

What's common between 6 and 3? 3, right? Cause 6 is 3 X 2.

 

So you take 3 outside:

 

3(2x -1)

 

does that make sense? or should i resort to drawing it on bitmap with colors or let somebody else answer??

 

:D :D

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:D

 

^ woah! zAk answered before me! and he did really concise! :D :D

 

Shakes head. I must learn the art of using a small amount of words!

 

:D :D :D :D

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:D

 

so are we clear now ?? :D

 

:D

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:D

wow it looks so complicated like that. :D

Maths is my fav subject and algebra is my fav topic. too bad i can't remember half of what i learnt in school. just have to refresh my memory! :D

:D

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:D

yeh, im learning that now for gcse

all you have to do is learn the method and then keep doing lots and lots of questions for practice and it will stay in your head.

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Mashallah. Good maths skills yiou guys have!

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