The "parent function" is y = (log to the base 2 of) x
The domain of this function is (0, infinity) (all real numbers greater than zero).
The range of this function is the same as above.
If you replace "x" with "x+1" in the parent function, the associated graph will look the same as that of the given function, EXCEPT that it will be translated by 1 unit to the left.
After this has happened, that "-3" will shift the entire new graph downward by 3 units.