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# AQA C1 Factorising with co efficient greater than one watch

1. Does anybody know a method I can use for factorising a quadratic with a co efficient of greater than 1, if it is 2 i can mostly always guess it through trial and error in my head however if it is high I don't know how to work it out.
For example for 12x^2 -7x - 12 = 0 i wouldn't know how to factorise it.

Can anybody recommend a method for me to learn in doing this for my C1 exam
2. (Original post by Sayless)
Does anybody know a method I can use for factorising a quadratic with a co efficient of greater than 1, if it is 2 i can mostly always guess it through trial and error in my head however if it is high I don't know how to work it out.
For example for 12x^2 -7x - 12 = 0 i wouldn't know how to factorise it.

Can anybody recommend a method for me to learn in doing this for my C1 exam
I do the a multiplied by c method.
An example is:

5x^2 + 11x + 6 = 0
5 x 6 = 30, find two numbers which times together to get 30 and add together to get 11, in this case 5 and 6.
Replace 11x with 5x and 6x
5x^2 + 5x + 6x + 6 = 0
Factorise the first half of the equation and the second.
5x(x+1) +6(x+1) = 0
You should get two brackets which are the same. Then you write:
(5x+6)(x+1)=0, put each answer equal to 0 and solve for your x values.
X= -6/5 and x=-1

Hope this helped

Posted from TSR Mobile
3. (Original post by Ben4)
I do the a multiplied by c method.
An example is:

5x^2 + 11x + 6 = 0
5 x 6 = 30, find two numbers which times together to get 30 and add together to get 11, in this case 5 and 6.
Replace 11x with 5x and 6x
5x^2 + 5x + 6x + 6 = 0
Factorise the first half of the equation and the second.
5x(x+1) +6(x+1) = 0
You should get two brackets which are the same. Then you write:
(5x+6)(x+1)=0, put each answer equal to 0 and solve for your x values.
X= -6/5 and x=-1

Hope this helped

Posted from TSR Mobile
yeah thats great thanks a lot i'll learn that
4. Hi, I've put this together quickly for you. It shows you how to solve a quadratic using a method which I've been using since GCSE.

Hope this helps!

[The previews seem to be really buggy, just click one of the thumbnails then you can navigate through them]

Attachment 469547469549Attachment 469547469549469600[attach]4.695474695494696e+23[/attach]
Attached Images

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Updated: October 16, 2015
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