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# Could someone explain this Expression?

1. Hi,

This is an example question and its solution. However, I don't understand a couple of things in it. Could somebody explain?

So, why does the '-6' disappear in stage 2? And, why does a minus sign appear in front of the 3?

Thanks!
2. In stage 2 you are adding like term 3 - 6 =-3
3. (Original post by Exceptional)
Hi,

This is an example question and its solution. However, I don't understand a couple of things in it. Could somebody explain?

So, why does the '-6' disappear in stage 2? And, why does a minus sign appear in front of the 3?

Thanks!
(Original post by Exceptional)
Hi,

This is an example question and its solution. However, I don't understand a couple of things in it. Could somebody explain?

So, why does the '-6' disappear in stage 2? And, why does a minus sign appear in front of the 3?

Thanks!
4. (Original post by EnterNamehereplz)
Ah, that makes sense! Thanks guys.
5. (Original post by EnterNamehereplz)
Using the same technique, is this correct?

6. (Original post by Exceptional)
Using the same technique, is this correct?
Well your second line is fine, and although the fourth line follows from the third line, the third line itself has some serious errors.

From:

We can remove the second bracket to get

Then the 2 and -2 will cancel, giving.

Can you finish from there?

You correctly handled the signs from inside the brackets, but the 40 and 288 were incorrect.
7. (Original post by ghostwalker)
Well your second line is fine, and although the fourth line follows from the third line, the third line itself has some serious errors.

From:

We can remove the second bracket to get

Then the 2 and -2 will cancel, giving.

Can you finish from there?

You correctly handled the signs from inside the brackets, but the 40 and 288 were incorrect.

Why do we take away the brackets from '-2'? Why not from (20-12^2)?

Would it just be 20-144? So -124?

Or are the brackets expanded? So -20 + 144? So 124?
8. (Original post by Exceptional)
Hi,

This is an example question and its solution. However, I don't understand a couple of things in it. Could somebody explain?

So, why does the '-6' disappear in stage 2? And, why does a minus sign appear in front of the 3?

Thanks!
Just gonna point out the fact that it should be a negative on the last line.
9. (Original post by RDKGames)
Just gonna point out the fact that it should be a negative on the last line.
Thanks!
10. (Original post by Exceptional)

Why do we take away the brackets from '-2'?
Because by convention, you are adding a negative number which is represented by +(-2) however this would also be the same as subtracting 2 so we ignore the brackets which would be represented by -2.

Why not from (20-12^2)?
Technically, you could indeed remove the brackets in the expression however you are treating the inside bracket as 2 separated terms therefore you would distribute the -1 accordingly, leaving you with .

Would it just be 20-144? So -124?
20-144 is indeed -124. Now when you consider -(20-144) you get -(-124) which turns into +124 within your equation.

Or are the brackets expanded? So -20 + 144? So 124?
Essentially, yes.

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