Find All Fixed Points for the Function by Setting the Function

Multiple Choice

Find all fixed points for the function by setting the function equal to x and solving the resulting equation for x.
-The length of a rectangular frame is 6 centimeters more than the width. The area inside the frame is 72 square centimeters. Find the width of the frame.

A) 18 centimeters
B) 12 centimeters
C) 8 centimeters
D) 6 centimeters