What number when added to 1 1/3 gives 2?

Taking algebra two apex courses and need with these questions

What is the y intercept of f(x)=(1/2)^x?

Describe the end behavior of the function below. f(x)=(2/3)^x-2 a. as x increases, f(x) approaches infinity. b. as x decreases, f(x) approaches 2. c. as x increases, f(x) approaches -2. d. as x decreases, f(x) approaches negative infinity.