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# Factorising watch

1. Hi, sorry to waste all you great mathmos' time with stupid questions like these. Anyway my problem is this:
Question: Factorise 8x2 + 4x
- My working: as x is common in x and x2 I put it outside the bracket and have this: x(8x + 4)
- Now my book says the answer is 4x(2x + 1) which I understand to be true. But, when I multiply out of the bracket for my one, it still gives 82 + 4x - is this still correct? There are many other questions like this, whereby my version works, yet the book says otherwise. Surely if mine was correct the book would state it? Please help someone, I am only 14 please don't think this is stupid.
2. What you've done is technically correct but it's not as simple as it could be. Usually when you get a question like this they want you to take out any common whole number factors as well - in this case you can take a factor 4 outside the bracket, but not a factor 8 because then you'd have a fraction 1/2 inside the bracket.
3. basically take out the highest term which is common to the equation, so 4x goes into both 8x^2 and 4x
4. take out the highest common term which is 4x in this case as it occurs in both numbers then put that on the outside

im not sure about ure books !! it can be very unhelpful if they arent correct but below is the correct answer !!

4x(2x+1) so when you multiply this out u get 2x X 4x and 1 x 4X

if u need to find x it would either be

4x=0

or

2x=-1
5. (Original post by bashment)
if u need to find x it would either be

4x=0

or

2x=-1
he never said it equals 0. don't confuse him with stuff he doesnt have to know
6. o and most people here aren't really great mathmos or anything.
7. Thankyou everyone, I understand it now.

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Updated: August 23, 2005
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