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Math Help

Posted: Fri Oct 26, 2007 1:38 am
by XemnasXD
don't think im retarded i spent a half a year in Pre-Calc and a full year in Calc. This stuff is basic algebra and you don't know how much it shames me for being confused but in my defense i always hated math.

So my brothers doing his math HW and he ask me for help heres the problem.


(X^-2)^-2
-------------
X^5

i said the answer was X^4/X^5

his friend said the answer was 1/X^9

i talked to said friend over the phone and he sounded very convincing while i was kinda like >>

Now heres the next problem

(2x^-3)^-2

i said the answer was 2x^6

his friend said the answer was 2/X^6

Im completely confused and lack all confidence in my math abilities at this point but i feel bad for not being able to help especially when i should know this stuff. So who is right here im right don't explain it if im wrong pls tell me why. And plz ppl im letting down my guard here don't lol @ me to much :?

Posted: Fri Oct 26, 2007 1:42 am
by crazyskwrls
((X^-2)^-2 )/X^5 = 1/x = X^4/X^5

(2x^-3)^-2 = 1/4x^6

^

for this one is it (2x^-3)^-2 or ((2x)^-3)^-2


if it is ((2x)^-3)^-2 = 64x^6= (2x)^6

thats my answer i am not exactly sure if it is right

Posted: Fri Oct 26, 2007 1:45 am
by Vandall
as I've said before; when in doubt answer is 7.5 8)

Posted: Fri Oct 26, 2007 1:46 am
by Xyzzzy
Vandall wrote:as I've said before; when in doubt answer is 7.5 8)

I'm going to pass my geometry test like that tommorow now

thanks

Posted: Fri Oct 26, 2007 1:49 am
by Vandall
Xyzzzy wrote:
Vandall wrote:as I've said before; when in doubt answer is 7.5 8)

I'm going to pass my geometry test like that tommorow now

thanks

you can't tell when im joking? :banghead:

Posted: Fri Oct 26, 2007 1:49 am
by Ell
Never mind for number 2 it's X^6/4

Posted: Fri Oct 26, 2007 1:49 am
by Beanstalk
If your dealing with negative exponents, then you must take the reciprocal of it, meaning move it to the bottom, and then you should knwo the rest, its basic fractions.

Posted: Fri Oct 26, 2007 1:58 am
by Dystopia
No, when in doubt, x=3, and y=2.

Posted: Fri Oct 26, 2007 2:06 am
by XemnasXD
Ell wrote:Never mind for number 2 it's X^6/4


are you sure about this?

Posted: Fri Oct 26, 2007 2:08 am
by crazyskwrls
i am pretty sure i am right :)

Posted: Fri Oct 26, 2007 2:08 am
by Dystopia
XemnasXD wrote:
Ell wrote:Never mind for number 2 it's X^6/4


are you sure about this?


Final answer...

Posted: Fri Oct 26, 2007 2:10 am
by Shadowman20818
1/X

(X^6)/4

Posted: Fri Oct 26, 2007 2:13 am
by Ell
XemnasXD wrote:
Ell wrote:Never mind for number 2 it's X^6/4


are you sure about this?

Yeah, you can test it by setting x as any number and seeing if they equal.

Posted: Fri Oct 26, 2007 2:13 am
by XemnasXD
say (2X^3)^2



by some of your logic i would square everything int he parenthesis so the answer would be 4X^6

Posted: Fri Oct 26, 2007 2:15 am
by Aiyas
crazyskwrls wrote:i am pretty sure i am right :)


You are, as far as I can see.

EDIT:
Ell is right on #2

(x^6)/4

Posted: Fri Oct 26, 2007 2:15 am
by Shadowman20818
XemnasXD wrote:say (2X^3)^2



by some of your logic i would square everything int he parenthesis so the answer would be 4X^6

Laws of exponents, yes you would do that.

Posted: Fri Oct 26, 2007 2:17 am
by XemnasXD
im getting conflicting answers.... :?

i trust Aiyas and Ell but Aiyas trust crazy whose answer is different from Ell's

Posted: Fri Oct 26, 2007 2:17 am
by Ell
crazyskwrls wrote:for this one is it (2x^-3)^-2 or ((2x)^-3)^-2


if it is ((2x)^-3)^-2 = 64x^6= (2x)^6

thats my answer i am not exactly sure if it is right

Those two equations are different.

Posted: Fri Oct 26, 2007 2:19 am
by XemnasXD
*explodes* how did i make it through HS....*cries* i took AP calc....i got a 2 thats not good but it means i at least got my name and 1 problem right :(

Posted: Fri Oct 26, 2007 2:19 am
by Aiyas
Let me clarify:

#1 1/x

#2 (x^6)/4

Posted: Fri Oct 26, 2007 2:20 am
by Ell
Aiyas wrote:Let me clarify:

#1 1/x

#2 (x^6)/4

Yay

Posted: Fri Oct 26, 2007 2:20 am
by XemnasXD
Aiyas wrote:Let me clarify:

#1 1/x

#2 (x^6)/4


how do you figure? can you explain in words...

Posted: Fri Oct 26, 2007 2:21 am
by crazyskwrls
crazyskwrls wrote:((X^-2)^-2 )/X^5 = 1/x = X^4/X^5

(2x^-3)^-2 = 1/4x^6

^

for this one is it (2x^-3)^-2 or ((2x)^-3)^-2



if it is ((2x)^-3)^-2 = 64x^6= (2x)^6

thats my answer i am not exactly sure if it is right



read the whole thing

Posted: Fri Oct 26, 2007 2:22 am
by Shadowman20818
crazyskwrls wrote:((X^-2)^-2 )/X^5 = 1/x = X^4/X^5

(2x^-3)^-2 = 1/4x^6

^

for this one is it (2x^-3)^-2 or ((2x)^-3)^-2


if it is ((2x)^-3)^-2 = 64x^6= (2x)^6

thats my answer i am not exactly sure if it is right

/sigh, here's where you went wrong

(2x^-3)^-2

1/(2x^-3)^2

you did: 1/(2^2*x^3(2)) rather than 1/(2^2x^-3(2))

Posted: Fri Oct 26, 2007 2:23 am
by crazyskwrls
XemnasXD wrote:
Aiyas wrote:Let me clarify:

#1 1/x

#2 (x^6)/4


how do you figure? can you explain in words...


for 1

x^4/X^5 which is what u got = xxxx/xxxxx

the four x cancel out leave 1 x on bottom = 1/x

Posted: Fri Oct 26, 2007 2:27 am
by XemnasXD
I give up ..... my brother and his math thx for all your help but i can honestly say im more confused now. but i know you guys actually took me serious and i really appreciate that (you don't know how much)

feel free to continue though if it'll bug you but im going back to do my safe chemistry work...where laws and rules are in english and everything makes sense...

Posted: Fri Oct 26, 2007 2:28 am
by crazyskwrls
Shadowman20818 wrote:
crazyskwrls wrote:((X^-2)^-2 )/X^5 = 1/x = X^4/X^5

(2x^-3)^-2 = 1/4x^6

^

for this one is it (2x^-3)^-2 or ((2x)^-3)^-2


if it is ((2x)^-3)^-2 = 64x^6= (2x)^6

thats my answer i am not exactly sure if it is right

/sigh, here's where you went wrong

(2x^-3)^-2

1/(2x^-3)^2

you did: 1/(2^2*x^3(2)) rather than 1/(2^2x^-3(2))


i had 2 answer for number 2 u can either consider:
2x as a whole
or
2 and x as separate

Posted: Fri Oct 26, 2007 2:29 am
by Ell
XemnasXD wrote:
Aiyas wrote:Let me clarify:

#1 1/x

#2 (x^6)/4


how do you figure? can you explain in words...

Anything to a negative power is just the reciprocal. So x^-1 equals 1/x^1, x^-2 equals 1/x^2, x^-3 equals 1/x^3 ect ect.

For problem one, (x^-2)^-2 is just (1/x^2)^-2 which is 1/((1/x^2)^2) and that equals 1/(1/x^4) which equals x^4. Divide that by x^5 and you get 1/x since the x's cancel.

Same thing for problem two. 2x^-3 equals 2/x^3. And (2/x^3)^-2 is 1/((2/x^3)^2) which is 1/(4/x^6) and that equals x^6/4.

Edit: The chemistry class I had was basically half math, so it was like taking one and a half math classes a day :banghead:

Posted: Fri Oct 26, 2007 2:30 am
by Aiyas
#1

(x^-2)^-2 / x^5

Multiply exponents in the numerator. (-2 * -2 = 4)

You should now have:

(x^4)/(x^5)

which is equivalent to:

x^(4-5) = x^-1 = 1/x

#2

(2x^-3)^-2

Rewrite as 1/(2x^-3)^2

Multiply the square to get 1/(4x^-6), or (1/4)*(1/(x^-6))

The second factor can be re-written as (x^-6)^-1, or x^(-6*-1), or x^6

So you have (1/4)*x^6, or x^6/4

Posted: Fri Oct 26, 2007 2:31 am
by Shadowman20818
crazyskwrls wrote:
Shadowman20818 wrote:
crazyskwrls wrote:((X^-2)^-2 )/X^5 = 1/x = X^4/X^5

(2x^-3)^-2 = 1/4x^6

^

for this one is it (2x^-3)^-2 or ((2x)^-3)^-2


if it is ((2x)^-3)^-2 = 64x^6= (2x)^6

thats my answer i am not exactly sure if it is right

/sigh, here's where you went wrong

(2x^-3)^-2

1/(2x^-3)^2

you did: 1/(2^2*x^3(2)) rather than 1/(2^2x^-3(2))


i had 2 answer for number 2 u can either consider:
2x as a whole
or
2 and x as separate

I'm pointing out that the 2 and x^-3 are separate one is done wrong.