# parabola problem

• May 2nd 2012, 11:15 AM
davellew69
parabola problem
hi all I have a question, and after a few hours of looking in my books I can`t find the answer.

I have the poin (-4,56) and I am asked to show if it is on the parabola, but I just cant remeber or find the solution?

sorry to be a pain

Dave
• May 2nd 2012, 11:29 AM
masters
Re: parabola problem
Quote:

Originally Posted by davellew69
hi all I have a question, and after a few hours of looking in my books I can`t find the answer.

I have the poin (-4,56) and I am asked to show if it is on the parabola, but I just cant remeber or find the solution?

sorry to be a pain

Dave

Hi davellew69,

Do you have the equation of the parabola? If so, substitute the coordinates you have into the equation and see if it makes it true. You really haven't given much detail to work with.
• May 2nd 2012, 11:32 AM
davellew69
Re: parabola problem
the equation is y+2x^2-7x-4 but I`m not sure what you mean by substuting
• May 2nd 2012, 11:38 AM
masters
Re: parabola problem
Quote:

Originally Posted by davellew69
the equation is y+2x^2-7x-4

Sorry, that's not an equation. Is it \$\displaystyle y=2x^2-7x-4\$? I think it is. Now, substitute your coordinates in for x and y and see if it is true.

\$\displaystyle (-4, 56) \Longrightarrow 56 = 2(-4)^2 - 7(-4)-4\$

Is that true? If it is, then the point (-4, 56) lies on the parabola.
• May 2nd 2012, 11:42 AM
davellew69
Re: parabola problem
lol got it, thanks, I must seem a right plonker
• May 2nd 2012, 11:46 AM
masters
Re: parabola problem
Quote:

Originally Posted by davellew69
lol got it, thanks, I must seem a right plonker

No worries, mate.