SOLUTION: What is the value of k so that the function f(x) = (x-6)/(2x+k) will be its own inverse?

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Question 1184782: What is the value of k so that the function f(x) = (x-6)/(2x+k) will be its own inverse?
Answer by josgarithmetic(39630) About Me  (Show Source):
You can put this solution on YOUR website!
x=%28y-6%29%2F%282y%2Bk%29-------just tried quickly switching x and y
%282y%2Bk%29x=y-6
2xy%2Bkx=y-6
2xy-y=-kx-6
y%282x-1%29=-kx-6
y=-%28kx%2B6%29%2F%282x-1%29


Want -%28kx%2B6%29%2F%282x-1%29=%28x-6%29%2F%282x%2Bk%29
-%28kx%2B6%29%282x%2Bk%29=%282x-1%29%28x-6%29
%28-kx-6%29%282x%2Bk%29=%28x-6%29%282x-1%29
Looking at left and right members correspond, highlight%28k=-1%29.