Question

Which set of points are collinear?
a.)A(-1,5); B(2,6); C(4,7)
b.)A(0,0); B(1/2,3); C(1,5)
c.)A(-4,-2); B(0,-4); C(2,-5)

Answer 1

Colinear points have the same slope between any two points. For example, for (b), slope between A and B
m(ab) = (yb-ya)/(xb-xa) = (3-0)/((1/2-0)=6
Between A and C:
m(ac) = (5-0)/(1-0)=5
Since m(ab)≠m(ac), the points are not colinear.
You can proceed to check the other choices for the right answer.

Answer 2

Thanks:)

Answer 3

You are welcome!

Answer 4

I have a PC, not a Mac. Can I make a "not equal sign" similar to the way Reiny explained about the square root sign?

Answer 5

You had posted the same question earlier and it was answered for you.

By reposting the identical question without checking on the status of your earlier post you cause tutors to spend unnecessary time duplicating an answer.

Make a note of the time you first posted the question and check back to see if it has been answered.

Answer 6

this is what I was referring to
http://www.jiskha.com/display.cgi?id=1276315330

Answer 7

Ok, I didn't mean to. The first time I posted it was a homework, the second time it was a review. So I didn't realize it was the same. I will make sure I keep track of my posting's from now on:)