converting equation to quadratic equation form

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onmyown
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converting equation to quadratic equation form

Postby onmyown » Mon Mar 28, 2011 8:47 pm

Hi,
can someone please help me help convert this equation into a quadratic equation (i.e. of the form y=ax^2+bx+c)
5(x/7-9)^2=7y+3

How would I go about simplifying the left side, I don't really know how to deal with x/7-9. How do I subtract x/7 and 9. I forgot how to do this :(
Just quickly tell me how to go about doing this. Especially how to solve the left side, thats what I'm really stuck on and am having a difficult time finding info last minute to remind me how to do this.
I can't quite seem to think straight right now, and I need to do this asap

PLEASE AND THANK YOU
I'd greatly appreciate it

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Martingale
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Re: converting equation to quadratic equation form

Postby Martingale » Mon Mar 28, 2011 10:56 pm

onmyown wrote:Hi,
can someone please help me help convert this equation into a quadratic equation (i.e. of the form y=ax^2+bx+c)
5(x/7-9)^2=7y+3

How would I go about simplifying the left side, I don't really know how to deal with x/7-9. How do I subtract x/7 and 9. I forgot how to do this :(
Just quickly tell me how to go about doing this. Especially how to solve the left side, thats what I'm really stuck on and am having a difficult time finding info last minute to remind me how to do this.
I can't quite seem to think straight right now, and I need to do this asap

PLEASE AND THANK YOU
I'd greatly appreciate it


Is this your equation...



?

onmyown
Posts: 18
Joined: Fri Dec 17, 2010 10:16 pm
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Re: converting equation to quadratic equation form

Postby onmyown » Tue Mar 29, 2011 12:19 am

Martingale wrote:
onmyown wrote:Hi,
can someone please help me help convert this equation into a quadratic equation (i.e. of the form y=ax^2+bx+c)
5(x/7-9)^2=7y+3

How would I go about simplifying the left side, I don't really know how to deal with x/7-9. How do I subtract x/7 and 9. I forgot how to do this :(
Just quickly tell me how to go about doing this. Especially how to solve the left side, thats what I'm really stuck on and am having a difficult time finding info last minute to remind me how to do this.
I can't quite seem to think straight right now, and I need to do this asap

PLEASE AND THANK YOU
I'd greatly appreciate it


Is this your equation...




?


yes that's it

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stapel_eliz
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Postby stapel_eliz » Tue Mar 29, 2011 12:22 am

onmyown wrote:

Multiply out the left-hand side. Subtract the 3 over to the left-hand side, and divide through by 7. Simplify to get "y=" the quadratic form. :wink:

onmyown
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Re:

Postby onmyown » Tue Mar 29, 2011 12:55 am

stapel_eliz wrote:
onmyown wrote:

Multiply out the left-hand side. Subtract the 3 over to the left-hand side, and divide through by 7. Simplify to get "y=" the quadratic form. :wink:


I understand that part.

I kind of just forgot how to do deal with the left-hand side. Specifically how to multiply it. How do I subtract x/7 and 9, and/or multiply x/7 with 5, and square x/7. :oops:

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stapel_eliz
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Postby stapel_eliz » Tue Mar 29, 2011 11:16 am

onmyown wrote:I kind of just forgot how to do deal with the left-hand side. Specifically how to multiply it.

To review how to multiply out the square, try this lesson. :wink:

onmyown
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Re:

Postby onmyown » Tue Mar 29, 2011 5:35 pm

stapel_eliz wrote:
onmyown wrote:I kind of just forgot how to do deal with the left-hand side. Specifically how to multiply it.

To review how to multiply out the square, try this lesson. :wink:


Yes, thank you very much.
I ended up getting this:

y=5x^2/343 - 90x/49 + 402/7

Can I simplify this even more? I know I can divide 402 by 7. But is it possible to simplify the x terms even more, and eliminate all the fractions.

If it is possible to simplify the x terms more, can you please explain to me how? For example, how do I divide 5x^2/343

that is all I am curious about it.

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stapel_eliz
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Postby stapel_eliz » Tue Mar 29, 2011 10:54 pm

I haven't checked your math, but since 343 is not a multiple of 5, clearly this fraction cannot be reduced. :wink:

onmyown
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Re:

Postby onmyown » Wed Mar 30, 2011 12:18 am

stapel_eliz wrote:I haven't checked your math, but since 343 is not a multiple of 5, clearly this fraction cannot be reduced. :wink:


makes sense

Thanks for bearing with my questions


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