[You_mo]

computer says..... no

[neelia]

Originally Posted by You_mo

computer says..... no

[Cornucopia]

Originally Posted by Moony

No - you arent following the rules posted above. You always resolve whats inside the brackets first - then work left to right with whats outside.

I don't think the rules are detailed enough. I think that x(a+b) is a single bracketed term - and my proof of that is that in algebra you can always expand the brackets to get (xa+xb).

[Moony]

Originally Posted by Cornucopia

I don't think the rules are detailed enough. I think that x(a+b) is a single bracketed term - and my proof of that is that in algebra you can always expand the brackets to get (xa+xb).

But your example isnt analogous to the problem the Op posed since to get x you would have to compute the terms outside the brackets first - thereby ignoring the rules on computation order.

But even if we take you example forward - the answer is stil 288

Since x in you example equals the terms outside the brackets i.e 48/2=24

Therefore expanding the bracket = (24*3 + 24*9) = (72 + 216) = 288

[Gneiss]

Originally Posted by Cornucopia

I think that x(a+b) is a single bracketed term - and my proof of that is that in algebra you can always expand the brackets to get (xa+xb).

Thanks for that, precisely the term I should have used earlier

[Doctor_Wibble]

Originally Posted by neelia

The one in the OP is not a valid mathematical expression

Are you sure about that?
It's poorly-written but not I think invalid.

[oldfogey101]

Originally Posted by Doctor_Wibble

No, it means that there is not necessarily a single answer. Mathematics does allow the existence of multiple possible answers to a single expression so this isn't really a problem.

The answer to that expression only has a single solution.

[Shady123]

Originally Posted by Moony

You calculate the bracket first - then work from left to right. You have worked right to left.

I still don't see it.

If it was 288 wouldn't it written 48 / 2 X (9+3) ?
I see it as the 48 is the left side of the equation and 2(9+3) being the right side so simplifying it to 48 / 24

[neelia]

Originally Posted by Doctor_Wibble

Are you sure about that?
It's poorly-written but not I think invalid.

Yes sure.

I suspect that it is not poorly written. I suspect that it has been specifically written to be ambiguous and thus mathematically not well defined and thus meaningless

[HenryGarten]

Originally Posted by neelia

Because
48÷2(9+3)
is not well defined.

48÷(2(9+3)) is

(48÷2)(9+3) is

That must be correct because it is exactly what I had written down earlier and then decided that my more cryptic reply was more appropiate.

[Doctor_Wibble]

Originally Posted by oldfogey101

The answer to that expression only has a single solution.

For the one in the OP - yes - but just to be clear, in that particular post I was making a more general point on ambiguity of questions and answers.

[neelia]

Originally Posted by HenryGarten

That must be correct because it is exactly what I had written down earlier and then decided that my more cryptic reply was more appropiate.

I like cryptic

[neelia]

Originally Posted by Doctor_Wibble

For the one in the OP - yes - but just to be clear, in that particular post I was making a more general point on ambiguity of questions and answers.

That is why I love Maths. It's lack of ambiguity

[Doctor_Wibble]

Originally Posted by neelia

I suspect that it has been specifically written to be ambiguous

No, really?

[Moony]

Originally Posted by Shady123

I still don't see it.

If it was 288 wouldn't it written 48 / 2 X (9+3) ?
I see it as the 48 is the left side of the equation and 2(9+3) being the right side so simplifying it to 48 / 24

No because in algebraic notation - the multiplication oprator can be written as a juxtaposition. The absence of a specified operator automatically implies multiplication.

[neelia]

Originally Posted by Doctor_Wibble

No, really?

lol but that makes it not poorly written, well written but meaningless

[oldfogey101]

Originally Posted by Moony

But your example isnt analogous to the problem the Op posed since to get x you would have to compute the terms outside the brackets first - thereby ignoring the rules on computation order.

But even if we take you example forward - the answer is stil 288

Since x in you example equals the terms outside the brackets i.e 48/2=24

Therefore expanding the bracket = (24*3 + 24*9) = (72 + 216) = 288

48/2(9+3)
48/(18+6)
48/24
=2

You can't say 2(9+3) does not equal (18+6), which is what you would be doing if you divided 48/2 instead.

[neelia]

Originally Posted by Moony

No because inalgebraic notation - the multiplication oprator can be written as a juxtaposition. The absence of a specified operator automatically implies multiplication.

yes if it is is clear what it is operating on. but that is not the case here and needs brackets to clarify

[Shady123]

Originally Posted by Moony

No because in algebraic notation - the multiplication oprator can be written as a juxtaposition. The absence of a specified operator automatically implies multiplication.

I give up. I never was very good at maths

[Cornucopia]

Originally Posted by Moony

But your example isnt analogous to the problem the Op posed since to get x you would have to compute the terms outside the brackets first - thereby ignoring the rules on computation order.

But even if we take you example forward - the answer is stil 288

Since x in you example equals the terms outside the brackets i.e 48/2=24

Therefore expanding the bracket = (24*3 + 24*9) = (72 + 216) = 288

Errr... no.

Only the 2 is connected to the bracket, and brackets are evaluated first. If it was intended that the 48 was also attached, it would be indicated with further brackets.

If we translate the OP's query to variables:-

a / b(c+d) = a / (bc + bd)

It's simply not (a/b)c + (a/b)d because that's not the rule for algebra.

I'm beginning to wonder whether the differences in interpretation owe more to people's backgrounds than anything else. i.e. some people interpret as for computing, whereas other interpret for algebra.

[Moony]

Originally Posted by oldfogey101

48/2(9+3)
48/(18+6)
48/24
=2

You can't say 2(9+3) does not equal (18+6), which is what you would be doing if you divided 48/2 instead.

The rules are that you work out whats inside the brackets first. Since 2 isnt inside the brackets - it has no business being included in the (9+3) part of the calculation.

[AlphaK]

In algebra there is no ambiguity 2y is (2*y) not 2*y , thus

24 ÷ 2y = 3
24 ÷ 3 = 2y
8 = 2y
4=y

but

24 ÷ 2(4) = 3 does not compute if this becomes 24 ÷ 2* (4) = 3
as 24 ÷ 2 * (4) is clearly 36

This is because 2(4) is actually (2*4) and not 2 *(4 )

So 48 ÷ 2 (12) is actually 48 ÷ (2 *12) and not 48 ÷ 2 * (12)

[neelia]

Originally Posted by oldfogey101

48/2(9+3)
48/(18+6)
48/24
=2

You can't say 2(9+3) does not equal (18+6), which is what you would be doing if you divided 48/2 instead.

you could just as easily say that you can't say that 48/2 isn't 96,

48/2(12) is as far as you can go with this without extra brackets

[Moony]

Originally Posted by Cornucopia

Errr... no.

Only the 2 is connected to the bracket.....

But its still outside of them. You calculate whats inside first.

[munta]

I had a bit of time on my hands so created this - hope you like it

http://www.youtube.com/watch?v=bwpWw-iVKHc