Find Value of k to Make 3 Points Collinear

[cheab14]

The question reads: find the value of k to make the points (3,9) (7, k), and (-1,6) collinear.

Does this involve using the distance formula? Whether or not it does, how would I go about solving this problem?

 

[rock.freak667]

The question reads: find the value of k to make the points (3,9) (7, k), and (-1,6) collinear.

Does this involve using the distance formula? Whether or not it does, how would I go about solving this problem?

What does collinear mean? That means that those 3 points lie on the same straight line.
So there are two methods you can use to find k.

You can find the straight line equation through all the points and then sub the co-ord you want to get.

OR you can use what you know about the slope of a line to aid you in an easier fashion.

 

[cheab14]

ok thank u!

 

[cheab14]

question 2

write an equation for the line that contains (0, 3) and is perpendicular to the line 6x-2y=1.

So for this question, I've found the slope of the line 6x-2y=1 which was 3. But would the slope for line (0, 3) be -1/3?

 

[HallsofIvy]

Yes.

 

[dexteronline]

By throwing your two known points (-1,6) and (3,9) into my linear regression online utility

I get the function y = 6.75 + 0.75 x
The resulting line graph shows the value 12 for k

Applet Link

http://thinkanddone.com/ge/Reg.html"

http://thinkanddone.com/ge/Reg.aspx"

 

[HallsofIvy]

Oh, dear! A "linear regression" utility to determine the equation of a line through 2 points. Do you use a calculator to add 1+ 1?

You're just "showin' off" aren't you dexteronline?

 

[dexteronline]

I could be done easier