find r for (-2,8), (r,4) m=-1/2

Question

Algebra 1 , find the slope 

Answer 1

The way to find the slope of the line between two points is to take the ratio of the difference of the y-coordinates and the difference of the x-coordinates in which is:

 

m=(y₂-y₁)/(x₂-x₁)

 

This problem has given slope with unknown x-coordinate. Substitute the variables for finding the slope and make it equal to the known slope in which is:

 

(4-8)/(r--2)=-4/(r+2)=-1/2.

 

The simplist way to solve for r is to cross multiply in which the equation becomes:

 

-1*(r+2)=-4*2. The negatives can drop out due to being on both sides of the equation. Hence,

 

r+2=8. Now, I'll let you finish this problem. (r,4)= ?.