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# C1 Maths help graphical question watch

1. I've attached a photo of the question:

I'm stuck on question b. Perhaps I'm being rather oblivious or stupid, but when I multiply out, I do not get the answer.

I did: (x+3)(x-1)^2

I did (x-1)^2 first to get: x^2 - 2x + 1

then multiplied with x+3 to get: 3x^3 - 6x^2 + 3x

I don't understand what I'm doing wrong!

Thanks for any help in advance.

2. (x^2 - 2x + 1)* x = x^3 - 2x^2 + x
(x^2 - 2x + 1)* 3 = 3x^2 - 6x +3

Add these together gives x^3 + x^2 - 5x + 3
So k = 3

The key on questions involving multiplying out brackets is to do it in that many steps. You'll make far less mistakes, and get more method marks.

If you're still not sure, or have any other questions, feel free to message me
3. (Original post by KnapAttackUK)
(x^2 - 2x + 1)* x = x^3 - 2x^2 + x
(x^2 - 2x + 1)* 3 = 3x^2 - 6x +3

Add these together gives x^3 + x^2 - 5x + 3
So k = 3

The key on questions involving multiplying out brackets is to do it in that many steps. You'll make far less mistakes, and get more method marks.

If you're still not sure, or have any other questions, feel free to message me
Thank you so much, solved my problem!
4. (Original post by L1000)
Thank you so much, solved my problem!
My pleasure, with my self discipline helping other people is the closest I come to revision
5. (Original post by KnapAttackUK)
My pleasure, with my self discipline helping other people is the closest I come to revision
Sorry to bug you again. But I'm having problems with this question too.

b. Simplify (16x^12)^3/4

I multiplied the two powers to get 9.

And I thought the answer was 16x^9, but it's 8x^9?

I've ran out of rep for today, but I will definitely give you one tomorrow, I really appreciate your help!
6. (Original post by L1000)
Sorry to bug you again. But I'm having problems with this question too.

b. Simplify (16x^12)^3/4

I multiplied the two powers to get 9.

And I thought the answer was 16x^9, but it's 8x^9?

I've ran out of rep for today, but I will definitely give you one tomorrow, I really appreciate your help!
No worries.

You need to do 16^(3/4) as well, which is 2^3, or 8.

Just think about how (2x)^2 is 4x^2, it's the same logic

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Updated: March 30, 2013
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