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  Discussion about math, puzzles, games and fun.   Useful symbols: √ ∞ ≠ ≤ ≥ ≈ ⇒ ∈ Δ θ ∴ ∑ ∫ π -

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Topic review (newest first)

Al-Allo
2013-07-03 08:57:08

Ah ok, thank you!

anonimnystefy
2013-07-03 08:55:19

That is correct!

Al-Allo
2013-07-03 08:47:31



Thanks bobbym

bobbym
2013-07-03 08:20:35

You can use codecogs to latex that expression correctly.

http://latex.codecogs.com/editor.php

Al-Allo
2013-07-03 07:25:00

{3^3*5^3} over {-3^2*5^2} rightarrow {-3*5} rightarrow =-15

bob bundy
2013-07-03 06:23:30

Evaluate



Bob

Al-Allo
2013-07-03 06:15:53

Actually, I was able to prove to myself that without brackets my answer would always be negative, no matter what. (which was the reason why I started this topic)
But yeah, a last one, just to be sure ! thank you

bob bundy
2013-07-03 05:50:33

Yes, that looks ok to me.

Would you like to try some more, just to be sure?

Bob

Al-Allo
2013-07-03 05:19:38

2^6 /-1^5 * 2^5 

2^1 /-1

-2

WOuld this be correct ? (Im trying it without the brackets)

And could you show me an example where the answer would'nt be negative ? (WITHOUt brackets...thanks )

bob bundy
2013-07-03 04:02:12

Do you want to know how to use



but when one of the xs is replaced by -x



So it will depend on whether n is odd or even.  odd means result will be minus.  even means result will be plus.

Bob

Al-Allo
2013-07-03 03:32:39

I don't think I made it clear what I wanted, the way you showed it to me bob, that I know. But I'm talking about the rules  of exponenets. ex :

2^6/-2^5 =

I know it will give me a 2^1 in my answer, but I don't know if it will stay positive or not. I could do the calculations like you did bob, but how would I know directly without doing them ?

bob bundy
2013-07-03 03:19:25

hi Al-Allo

For the rules of precedence see

http://www.mathsisfun.com/operation-order-bodmas.html

So



As it happens you would get the same result if you did (-2)^5



So here is a similar example where the denominator has an even power



Whereas




Bob

bobbym
2013-07-03 03:13:18

Hi;

Because they love to be tricky.

If you assume the second alternative in Bob's suggestion you are asking where does the minus sign go in -2^5. The answer, nowhere!

But the other one (-2)^5 that illustrates a principle.

Al-Allo
2013-07-03 03:03:27

And why would it be that way ?

bobbym
2013-07-03 03:02:24

Hi;

bob bundy wrote:

depends whether it says (-2)^5 or -(2^5)

Without the brackets the minus sign stays.

I would think they would be asking the first one though.

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