Math problem please help

hyelakingsfan · Post by **hyelakingsfan** » Fri Nov 04, 2005 8:42 pm

Thanks for helping everyone

kittens wrote:You square both side and get:

2x - 1 = 16 + (x - 4) - 8(x - 4)^(1/2)
8(x - 4)^(1/2) = 13 - x
64(x - 4) = (13 - x)^2

then do the rest.....

For this one i got confused...if you square both sides dont u get

kittens · Post by **kittens** » Fri Nov 04, 2005 9:47 pm

hyelakingsfan wrote:Thanks for helping everyone

kittens wrote:You square both side and get:

2x - 1 = 16 + (x - 4) - 8(x - 4)^(1/2)
8(x - 4)^(1/2) = 13 - x
64(x - 4) = (13 - x)^2

then do the rest.....
For this one i got confused...if you square both sides dont u get

Nopes

Suppose if you have (a - b)^2. Then we have: (a - b)^2 = a^2 - 2ab + b^2. This is a formura.

Then simplly, you substitute a = 4 and b = (x - 4)^(1/2), then we get:
(4 - (x - 4)^(1/2))^2 = 4^2 - 2*[4*(x - 4)^(1/2)] + [(x - 4)^(1/2)]^2
= 16 - 8(x - 4)^(1/2) + (x - 4)
= 12 + x - 8(x - 4)^(1/2).

Sakura-chan · Post by **Sakura-chan** » Fri Nov 04, 2005 9:52 pm

Yah, what she said LOL. Call me nuts, but I think algebra is soooo cool

... I guess it's because I don't study it anymore that I say that

. But I really liked it when I was in college.

kittens · Post by **kittens** » Fri Nov 04, 2005 9:54 pm

Sakura-chan wrote:Yah, what she said LOL. Call me nuts, but I think algebra is soooo cool ... I guess it's because I don't study it anymore that I say that . But I really liked it when I was in college.

Ah, algebra rocks

I just loooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooove polynomials (seriously!). Also algebra is all about polynomials!

Sakura-chan · Post by **Sakura-chan** » Fri Nov 04, 2005 9:57 pm

kittens wrote:
Sakura-chan wrote:Yah, what she said LOL. Call me nuts, but I think algebra is soooo cool ... I guess it's because I don't study it anymore that I say that . But I really liked it when I was in college.
Ah, algebra rocks I just loooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooove polynomials (seriously!). Also algebra is all about polynomials!

Kittens... we must have been related in a past life or something XD...

kittens · Post by **kittens** » Fri Nov 04, 2005 9:59 pm

Sakura-chan wrote:
Kittens... we must have been related in a past life or something XD...

Heeheehee! That is too funny

Probablly

kittens · Post by **kittens** » Fri Nov 04, 2005 10:14 pm

BTW, make sure that at the last x = 85 is NOT a solution to the original problem (since we square the original problem we have an extra solution.....).

So your HW is (:P

see so you know why I am a math professor??

) is to think why 85 is NOT a solution to the original problem but this is a solution for 64(x - 4) = (13 - x)^2.

hyelakingsfan · Post by **hyelakingsfan** » Fri Nov 04, 2005 10:29 pm

oooo ok. I get it now. Thanksyou soooooooooooooooooooooooooooooooooooooooo *takes breathe* oooooooooooooooooooooooooooooo muchhhhhhhh

hyelakingsfan · Post by **hyelakingsfan** » Fri Nov 04, 2005 10:40 pm

So does anyone know this one??

Hi Kittens!!

kittens · Post by **kittens** » Fri Nov 04, 2005 10:52 pm

hyelakingsfan wrote:So does anyone know this one??

Hi Kittens!!

Do you want to simplify this?

3^(1/4)/[2*4^(1/4)] = 3^(1/4)/[2*2^(1/2)] * [2^(1/2)]/[2^(1/2)] (since 4^(1/4) = 2^(1/2))
= 3^(1/4)*2^(1/2)/[2*2^(1/2)*2^(1/2)]
=3^(1/4)*2^(1/2)/4
=3^(1/4)*4^(1/4)/4
=12^(1/4)/4

hyelakingsfan · Post by **hyelakingsfan** » Fri Nov 04, 2005 11:22 pm

it says rationalize the denominator and simplify

But in the book it says to do it like this. Is that wrong?

and then from there i dunno (if thats right)

kittens · Post by **kittens** » Sat Nov 05, 2005 12:00 am

hyelakingsfan wrote:it says rationalize the denominator and simplify

But in the book it says to do it like this. Is that wrong?

and then from there i dunno (if thats right)

First of all, the denominator should be 8 in this case...... So this should be typo.

If you do this I think both answer should be correct..... (b/c 4^(3/4) = 2*(4)^(1/4)).

But you have to be careful, like I said I cannot add or multiply

hyelakingsfan · Post by **hyelakingsfan** » Sat Nov 05, 2005 12:20 am

hmmm *scratches head* ok i think ill just go with what u say. Your smarter than this stupid book lol.

Thank you once again. :yourock:

kittens · Post by **kittens** » Sat Nov 05, 2005 12:23 am

hyelakingsfan wrote:hmmm *scratches head* ok i think ill just go with what u say. Your smarter than this stupid book lol. Thank you once again.

Thanks

But yeah...... books often have typos (esp in a solution set). This is b/c authors do not pay too much attentions to answers

Also mathematicians cannot usually add or mult

so be nice

evilminion · Post by **evilminion** » Sat Nov 05, 2005 1:22 am

Heh... I hereby join the "quietly sneaking out the back door" crowd. Oddly, I majored in Statistical Psychology, and only minored in English, but fifteen or so years later, I can conjugate a whole lot better than I can commute.

And before the resident pervs say anything, there is a big difference between "conjugate" and "conjugal". For one thing, the former isn't illegal to perform in public.