SOLUTION: I don't understand this: find the value of k if the line joining (4,k) and (3,1) is parallel to the line y=-1/2x-9/2

Algebra ->  Coordinate-system -> SOLUTION: I don't understand this: find the value of k if the line joining (4,k) and (3,1) is parallel to the line y=-1/2x-9/2      Log On


   

Question 147837: I don't understand this: find the value of k if the line joining (4,k) and (3,1) is parallel to the line y=-1/2x-9/2
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
If lines are parallel, it means their slopes are equal.
The line has a slope of (-1/2).
The formula for the slope given two points is,
m=%28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29
m=%281-k%29%2F%283-4%29=%281-k%29%2F%28-1%29=k-1
For parallel lines, set the slope equal to (-1/2) and solve for k.
k-1=-1%2F2
k=1%2F2

Here is a graph of the line, the two points and the new line.