The domain of any function is the number that you can put in for x. Since the highest number possible for x is 2, this means x must always be 2 or lower. Therefore we can write it as x ≤ 2
F(x) = one fourth to the power of x-2 f(x) = (1/4)^(x-2) It is a decreasing function that when x= 2, (1/4) is raised to the zero power which is 1, which is what the point (2,1) asks for.