I don't even know to to start on this problem. It doesn't even give you any coordinates at all so how am I suppose to find the equation for this line?

http://i45.tinypic.com/1y2zpe.jpg

Printable View

- February 1st 2010, 07:56 PMnox16Finding equation for a line?
I don't even know to to start on this problem. It doesn't even give you any coordinates at all so how am I suppose to find the equation for this line?

http://i45.tinypic.com/1y2zpe.jpg - February 1st 2010, 08:01 PMpickslides
Well the equation of a line in this case can be given by

They have told you that so

They have also told you the line shares a point with the parabola. This point is so

Now solve for and your done. - February 1st 2010, 08:06 PMsnaes
Use the form

m is slope

b is y intercept

m=4 (given)

Put in the equation:

We are given in the graph a point x=2 there is an interception with the graph

so or at that point.

Now you know the point (2,4) is on the graph.

put in 2 for x and 4 for y in the and solve for b:

now you are done!

- February 1st 2010, 08:06 PMnox16
Nevermind snaes answered my question. Thank you so much for helping me with this question!

I just got the answer and it is y = 4x -4. I think you kind of got it mixed up snaes. - February 1st 2010, 08:08 PMpickslides
correct.

- February 1st 2010, 08:13 PMbigwave
also another way to get

is to use the point slope form

so using point x = 2 and since y=2^2 = 4 with have the point (2,4)

then

- February 1st 2010, 08:16 PMpickslides
- February 1st 2010, 08:26 PMnox16
Thank you so much for your help guys I really appreciate it. Now I am stuck on this problem. How would I find out the slope of it? I already plugged in the x and y intercepts it gave me into the equation y = x^2 + 1 and got the coordinate (square root of 7, 5). I'm thinking the top of the triangle is 10 and the right side might be 1 but I'm not quite sure. So that makes it a rise over run of 1/10. Is that the correct slope?

http://i48.tinypic.com/n3of1d.jpg - February 1st 2010, 08:34 PMbigwave
you have to do the rise/run based on the 2 points

first find the (x,y) of the 2 intersecting points

then use for the slope

as you have found

and

then

then just simplify

I got but double check this - February 1st 2010, 09:04 PMnox16
I don't think that is the right answer. Here's what it says in the back of the book: http://i46.tinypic.com/2zokck9.jpg

At this time I got the slope 3/sqrt{7} - 2 and is trying to plug in (2,5) into the equation y = mx + b. But I get stuck at this point 5 = 3/sqrt{7} - 2 (2) + b - February 2nd 2010, 12:15 PMpickslides
- February 2nd 2010, 03:50 PMnox16
Thanks so much for helping me with this problem.