SOLUTION: Using the distance formula, determine whether the following points are collinear: A(0,4) B(7,-6) C(-5,11) I thought i had to find the distance between A and B, and then B and C,

Algebra ->  Length-and-distance -> SOLUTION: Using the distance formula, determine whether the following points are collinear: A(0,4) B(7,-6) C(-5,11) I thought i had to find the distance between A and B, and then B and C,      Log On


   

Question 259832: Using the distance formula, determine whether the following points are collinear:
A(0,4) B(7,-6) C(-5,11)
I thought i had to find the distance between A and B, and then B and C, and then A and C but I am not sure.
Answer by drk(1908) About Me  (Show Source):
You can put this solution on YOUR website!
To determine colinear we need " slope" not distance. A(0,4) B(7,-6) C(-5,11)
The slope formula is
m+=++%28y2-y1%29%2F%28x2-x1%29
--
Using A and B we get
m+=++%28-6-4%29%29 /%287-0%29
So, m = -10/7
--
Using A and C we get
m+=++%2811-4%29%29/%28-5-0%29
So, m = -7/-5 = 7/5.
Since these are not the same, they are not colinear