The Purplemath Forums

by **onmyown** on 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

**Sponsor**

by **Martingale** on 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...

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

?

by **onmyown** on 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...

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

?

yes that's it

by **stapel_eliz** on Tue Mar 29, 2011 12:22 am

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. :wink:

by **onmyown** on Tue Mar 29, 2011 12:55 am

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. :oops:

by **stapel_eliz** on 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:

by **onmyown** on 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.

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.

by **stapel_eliz** on 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:

by **onmyown** on 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.

makes sense

Thanks for bearing with my questions

The Purplemath Forums

converting equation to quadratic equation form

converting equation to quadratic equation form

Re: converting equation to quadratic equation form

Re: converting equation to quadratic equation form

Re:

Re:

Re: