The easiest way to solve this is to run through a couple of points to see what can be eliminated.
x = 0 is a good one to test. Why?
Because you are going to get either 2 or 1/2 when you are done. That will eliminate 2 of the answers.
For A and D
f(x) = 2(1/2)^x
f(0) = 2(1/2)^0 But anything to the 0 power is 1.
f(0) = 2
That answer eliminates A and D
For C and B
if x = 1, f(1) should also = 1
The point you are testing is 1,1
f(1) = 1 in B
f(x) = 1/2(2)^1
f(1) = 1/2(2)^1
f(1) = 1/2(2)
f(1) = 1 It looks like B is the answer, but with this kind of question, you should use the third point. (-1,0.25)
f(-1) = 1/2(2)^-1
but 2^-1 = 1/2
f(-1) = 1/2 * 1/2
f(-1) = 1/4, but as a decimal, 1/4 = 0.25
f(-1) = 0.25
B <<<<< Answer
