IGCSE maths factorising question help

SuchBants

8

Hi,
Could someone help with this and explain each step? :

Thanks

Reply 1

maggiehodgson

14

Original post by SuchBants

Hi,
Could someone help with this and explain each step? :

Thanks

Hope that the attached document is enough explanation

OP

Original post by maggiehodgson

Hope that the attached document is enough explanation

I get the common factor but where does the plus 1 come from.

Reply 3

I'm_infires

11

(X-1)(3x-2) = 3x^2 - 2x - 3x + 2
= 3x^2 - 5x + 2

Expand the second bracket with the all elements (?) of the first bracket seperately. What you basically do when expanding this is x (3x-2) and -1 (3x-2) and then add the products of these together.

I'm not good at explaining this but if you had another problem like (x^2-3x-2)(x-2), you would multiply x^2 (x-2) then -3x (x-2) & -2 (×-2) and add all products together to get the simplest form.

Posted from TSR Mobile

(edited 8 years ago)

Reply 4

maggiehodgson

14

Original post by SuchBants

I get the common factor but where does the plus 1 come from.

The second term is (x-1) but this is really (x-1)times by 1

if you were to factorise 3x^2 + x it would be x(3x + 1) because x is x times 1.

Does that help?

Reply 5

Notnek

21

Original post by I'm_infires

(X-1)(3x-2) = 3x^2 - 2x - 3x + 2
= 3x^2 - 5x + 2

Expand the second bracket with the all elements (?) of the first bracket seperately. What you basically do when expanding this is x (3x-2) and -1 (3x-2) and then add the products of these together.

I'm not good at explaining this but if you had another problem like (x^2-3x-2)(x-2), you would multiply x^2 (x-2) then -3x (x-2) & -2 (×-2) and add all products together to get the simplest form.

Posted from TSR Mobile

You seem to be explaining how to expand two brackets.

But that's not what the OP asked.

Reply 6

♥Samantha♥

19

1) factorise out (x-1):
(x-1)[3(x-1) + 1]

2) expand 2nd bracket
(x-1)(3x-3+1) = (x - 1)(3x - 2)

Reply 7

I'm_infires

11

Original post by notnek

You seem to be explaining how to expand two brackets.

But that's not what the OP asked.

Yeah, I realised later on. It was because I couldn't see the maths question that the OP put a picture of so I thought that the pdf was the OP uploading the pic again or something but that was someone else :P

IGCSE maths factorising question help

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