## converting equation to quadratic equation form

Simplificatation, evaluation, linear equations, linear graphs, linear inequalities, basic word problems, etc.
onmyown
Posts: 18
Joined: Fri Dec 17, 2010 10:16 pm
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### converting equation to quadratic equation form

Hi,
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

I'd greatly appreciate it

Martingale
Posts: 350
Joined: Mon Mar 30, 2009 1:30 pm
Location: USA
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### Re: converting equation to quadratic equation form

onmyown wrote:Hi,
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

I'd greatly appreciate it

$5\left(\frac{x}{7}-9\right)^2=7y+3$

?

onmyown
Posts: 18
Joined: Fri Dec 17, 2010 10:16 pm
Contact:

### Re: converting equation to quadratic equation form

Martingale wrote:
onmyown wrote:Hi,
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

I'd greatly appreciate it

$5\left(\frac{x}{7}-9\right)^2=7y+3$

?

yes that's it

stapel_eliz
Posts: 1738
Joined: Mon Dec 08, 2008 4:22 pm
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onmyown wrote:$5\left(\frac{x}{7}-9\right)^2=7y+3$

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.

onmyown
Posts: 18
Joined: Fri Dec 17, 2010 10:16 pm
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### Re:

stapel_eliz wrote:
onmyown wrote:$5\left(\frac{x}{7}-9\right)^2=7y+3$

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.

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.

stapel_eliz
Posts: 1738
Joined: Mon Dec 08, 2008 4:22 pm
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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.

onmyown
Posts: 18
Joined: Fri Dec 17, 2010 10:16 pm
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### Re:

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.

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.

stapel_eliz
Posts: 1738
Joined: Mon Dec 08, 2008 4:22 pm
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I haven't checked your math, but since 343 is not a multiple of 5, clearly this fraction cannot be reduced.

onmyown
Posts: 18
Joined: Fri Dec 17, 2010 10:16 pm
Contact:

### Re:

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

makes sense

Thanks for bearing with my questions