algebrax1
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#1
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Hi! I need help with a maths question.
1a) Fully factorise 3x2 - 10x - 8
I worked that out to be (3x+2)(x-4)

Then for part b it says use your answer to part (a) to factorise the expression 3(x+1)2 - 10(x+1)-8

How would I go about doing this?
Thank you!
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Devify
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(Original post by algebrax1)
Hi! I need help with a maths question.
1a) Fully factorise 3x2 - 10x - 8
I worked that out to be (3x+2)(x-4)

Then for part b it says use your answer to part (a) to factorise the expression 3(x+1)2 - 10(x+1)-8

How would I go about doing this?
Thank you!
Look what they both have in common.

3x2 - 10x - 8
3(x+1)2 - 10(x+1)-8

You can see that they're both the same except that the x is replaced by (x+1) so it's basic substitution.
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algebrax1
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(Original post by Devify)
Look what they both have in common.

3x2 - 10x - 8
3(x+1)2 - 10(x+1)-8

You can see that they're both the same except that the x is replaced by (x+1) so it's basic substitution.
Thanks. Could you please show me step by step? That would be really appreciated
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Jamdroid
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(Original post by algebrax1)
Thanks. Could you please show me step by step? That would be really appreciated
You've already factorised it.

Just replace every x in your factorised equation in part a) with (x+1)

For example...
(3x+1) would become (3(x+1)+1) which can be simplified to (3x+4).

Try it for yourself and we can check if you've done it correctly
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algebrax1
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(Original post by Jamdroid)
You've already factorised it.

Just replace every x in your factorised equation in part a) with (x+1)

For example...
(3x+1) would become (3(x+1)+1) which can be simplified to (3x+4).

Try it for yourself and we can check if you've done it correctly
I completely understand now! Thank you so much
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