help with algebra

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icw
Posts: 3
Joined: Mon Dec 31, 2012 10:39 am

help with algebra

Post by icw »

Hi can anyone help with a simple problem, as I am not sure I am helping my dd correctly

2dr²p

Should the above be re-written as

2xdxrxrxp
or
2xdx(rxr)xp

or does it not matter?
twelveminus
Posts: 208
Joined: Sun Sep 23, 2012 7:58 pm

Re: help with algebra

Post by twelveminus »

2dr²p

is equivalent to

2 * d * r * r * p

No brackets are required, since all the operations are the same (multiplication).

Extra brackets can be useful, as in for example

((2 + 6) * 3) +
((3 + 4) * 4)

which is clearer than

(2 + 6) * 3 + (3 + 4) * 4

even though it gives the same answer

But in this case brackets, while not changing the result, are undesirable.
icw
Posts: 3
Joined: Mon Dec 31, 2012 10:39 am

Re: help with algebra

Post by icw »

Thanks for the swift response :D
icw
Posts: 3
Joined: Mon Dec 31, 2012 10:39 am

Re: help with algebra

Post by icw »

hi again
Can you help with another one

7+4x3 = 19
Does this need the brackets i.e
7+(4x3) = 19

or do we assume that in BODMAS multiplication comes before addition etc so we don't need to show the brackets ?
twelveminus
Posts: 208
Joined: Sun Sep 23, 2012 7:58 pm

Re: help with algebra

Post by twelveminus »

they are identical, the brackets may clarify, and are not harmful, but they are not necessary
AEC
Posts: 9
Joined: Sat Jun 23, 2012 6:07 pm

Re: help with algebra

Post by AEC »

icw wrote:Hi can anyone help with a simple problem, as I am not sure I am helping my dd correctly

2dr²p

Should the above be re-written as

2xdxrxrxp
or
2xdx(rxr)xp

or does it not matter?
They all the same and it doesn't really matter when you trying to answer the question, however, final answer should be written as
2dr²p, becasuse this form is more simplified than the other two.

Regards
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