SOLUTION: Find the value of k so that the line containing the points (6,8) and (k,6) is parallel to the line containing the points (−7,−9) and (0,−12).

Algebra ->  Linear-equations -> SOLUTION: Find the value of k so that the line containing the points (6,8) and (k,6) is parallel to the line containing the points (−7,−9) and (0,−12).      Log On


   

Question 785280: Find the value of k so that the line containing the points (6,8) and (k,6) is parallel to the line containing the points (−7,−9) and (0,−12).
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Slope of first pair, %288-6%29%2F%286-k%29=2%2F%286-k%29.
Slope of second pair, %28-9-%28-12%29%29%2F%28-7-0%29=-3%2F7

In order for the lines of each pair to be perpendicular, their slopes must be negative reciprocals of eachother:
2%2F%286-k%29=7%2F3
2=7%286-k%29%2F3
6=7%286-k%29
6=42-7k
7k=42-6
7k=36
k=36%2F7

Your other two questions are handled similarly.