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 Post subject: Algebra.Posted: Wed, 11 Jan 2012 01:22:35 UTC
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Joined: Sun, 25 Dec 2011 00:28:25 UTC
Posts: 95
Hi, again

I've got 2 tasks.

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 Post subject: Re: Algebra.Posted: Wed, 11 Jan 2012 02:33:11 UTC
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Joined: Wed, 30 Mar 2005 04:25:14 UTC
Posts: 12102
Location: Austin, TX
kreshnik wrote:
Hi, again

I've got 2 tasks.

For the first one, multiply through by , and then move the rest of the stuff to the right side and solve. For the second one, square your given, and divide by 4.

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 Post subject: Re: Algebra.Posted: Wed, 11 Jan 2012 16:47:09 UTC
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Joined: Sun, 25 Dec 2011 00:28:25 UTC
Posts: 95
Quote:
For the first one, multiply through by , and then move the rest of the stuff to the right side and solve. For the second one, square your given, and divide by 4.

I still can't solve it!

But I need steps.
And I'm still stuck here. And for the second one, I have no idea what should I do, If you don't mind please try to help me with numbers not with words,
it's quite hard to understand you (because English is foreign language for me), if you're already bored with my dizzy tasks, just let me know, it's OK.

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 Post subject: Re: Algebra.Posted: Wed, 11 Jan 2012 16:49:39 UTC
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Joined: Mon, 29 Dec 2008 17:49:32 UTC
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kreshnik wrote:
Quote:
For the first one, multiply through by , and then move the rest of the stuff to the right side and solve. For the second one, square your given, and divide by 4.

I still can't solve it!

But I need steps.
And I'm still stuck here. And for the second one, I have no idea what should I do, If you don't mind please try to help me with numbers not with words,
it's quite hard to understand you (because English is foreign language for me), if you're already bored with my dizzy tasks, just let me know, it's OK.

For the first one, you have a quadratic equation in (namely ) which you should solve. What do you get for the second one following Shadow's suggestion?

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 Post subject: Re: Algebra.Posted: Wed, 11 Jan 2012 18:19:46 UTC
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Joined: Sun, 24 Jul 2005 20:12:39 UTC
Posts: 3692
Location: Ottawa Ontario
On the 1st one, OM's suggestion will lead to 2^x = 1/8 or -4;
you will use 2^x = 1/8, NOT 2^x = -4 ; OK?

Also, usually easier if you substitute, like let a = 2^x:
8a^2 + 31a - 4 = 0

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 Post subject: Re: Algebra.Posted: Wed, 11 Jan 2012 22:07:39 UTC
 Senior Member

Joined: Sun, 25 Dec 2011 00:28:25 UTC
Posts: 95
outermeasure wrote:
For the first one, you have a quadratic equation in (namely ) which you should solve. What do you get for the second one following Shadow's suggestion?

Denis wrote:
On the 1st one, OM's suggestion will lead to 2^x = 1/8 or -4;
you will use 2^x = 1/8, NOT 2^x = -4 ; OK?

Also, usually easier if you substitute, like let a = 2^x:
8a^2 + 31a - 4 = 0

Thanks a lot guys I used a quadratic equation as outermeasure said, and I used Denis' advice: and I did it like:

For we have:

For we have

For the second one... I've come up with a solution:

So we have now:

since:

Thanks a lot again everyone for the help.

Now I would like to know how did shadow think about his way of doing it.

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 Post subject: Re: Algebra.Posted: Wed, 11 Jan 2012 22:15:58 UTC
 Moderator

Joined: Wed, 30 Mar 2005 04:25:14 UTC
Posts: 12102
Location: Austin, TX
kreshnik wrote:
outermeasure wrote:
For the first one, you have a quadratic equation in (namely ) which you should solve. What do you get for the second one following Shadow's suggestion?

Denis wrote:
On the 1st one, OM's suggestion will lead to 2^x = 1/8 or -4;
you will use 2^x = 1/8, NOT 2^x = -4 ; OK?

Also, usually easier if you substitute, like let a = 2^x:
8a^2 + 31a - 4 = 0

Thanks a lot guys I used a quadratic equation as outermeasure said, and I used Denis' advice: and I did it like:

For we have:

For we have

For the second one... I've come up with a solution:

So we have now:

since:

Thanks a lot again everyone for the help.

Now I would like to know how did shadow think about his way of doing it.

_________________
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(O.o)
(> <)
This is Bunny. Copy Bunny into your signature to help him on his way to world domination

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 Post subject: Re: Algebra.Posted: Thu, 12 Jan 2012 06:26:17 UTC
 Member of the 'S.O.S. Math' Hall of Fame

Joined: Sun, 24 Jul 2005 20:12:39 UTC
Posts: 3692
Location: Ottawa Ontario
kreshnik wrote:
Now I would like to know how did shadow think about his way of doing it.

He solveth in mysterious ways...

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 Post subject: Re: Algebra.Posted: Thu, 12 Jan 2012 15:13:25 UTC
 Senior Member

Joined: Sun, 25 Dec 2011 00:28:25 UTC
Posts: 95

Huh, now it's better, thanks anyway.

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