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September 11th, 2013, 05:27 PM   #1
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Math Homework Help "Extend and Challenge" Questions

Hey,

I'd really appreciate help on these questions and how to solve them. For the first one, I had no idea how to do it (Q#13).

On the second one, this is what I got up too (Q#14).
1. Cube each Side
- m+9 = 27 + 27THIRDROOTOF(m-9) + 9(2/3)ROOTOF(m-9) + m-9

2. Rearrange and Sub x for THIRDROOTOF(m-9)

- 0=9+27x+9x^2

3. Divide both sides by 9

0 = 1 + 3x + x^2

4. (Here I got lost so I just tried to do stuff to help me out.)

0 = 1 + 3x +x^2 -x +x
0 = 1 + 2x + x^2 + x
0 = (1+x)^2 + x

http://img194.imageshack.us/img194/1097/kvgc.jpg
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September 11th, 2013, 06:32 PM   #2
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Re: Math Homework Help "Extend and Challenge" Questions

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September 11th, 2013, 08:38 PM   #3
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Re: Math Homework Help "Extend and Challenge" Questions

Hello, Tzad!

Quote:




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[color=beige]. . . . . . . . [/color]








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September 13th, 2013, 03:14 PM   #4
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Re: Math Homework Help "Extend and Challenge" Questions

Quote:
Originally Posted by greg1313
Hey Greg! Thanks for the help!

I wanted to know what you did between steps 4 and 5.

Thanks,
Tzad
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September 13th, 2013, 03:17 PM   #5
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Re: Math Homework Help "Extend and Challenge" Questions



Does that help?
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September 13th, 2013, 06:59 PM   #6
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Quote:
Originally Posted by Tzad
0 = 1 + 3x + x^2
0 = 1 + x(3 + x)
x(3 + x) = -1
(m - 9)(m + 9) = -1
m = 81 - 1 = 80
|m| = 4?5
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September 14th, 2013, 11:32 AM   #7
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Re: Math Homework Help "Extend and Challenge" Questions



To Greg and Skip....I'm confused and hope to learn something here...

I followed your work to arrive at m = 4SQRT(5), but that I'm quite sure
is not the solution for the above equation...
http://www.wolframalpha.com/input/?i=%2 ... +-+3+%3D+0

So what did I miss? Thanks guys!
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September 14th, 2013, 01:43 PM   #8
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Re: Math Homework Help "Extend and Challenge" Questions

Quote:
Originally Posted by greg1313


Does that help?
Thank you!

It helped me a lot.
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September 14th, 2013, 01:51 PM   #9
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Re: Math Homework Help "Extend and Challenge" Questions

Quote:
Originally Posted by Denis
So what did I miss?
I don't think that would be the first time W|A has been wrong. Check it with a calculator.
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September 14th, 2013, 01:59 PM   #10
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Re: Math Homework Help "Extend and Challenge" Questions

Quote:
Originally Posted by greg1313
Quote:
Originally Posted by Denis
So what did I miss?
I don't think that would be the first time W|A has been wrong. Check it with a calculator.
I want to wire you money for helping me.

What is your paypal email?
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