You can put this solution on YOUR website! Domain: (-infinity, infinity)
Range: (-3, infinity)
Note that -3 is not included in the range since there is no finite number x such that 4^x - 3 = -3 (otherwise the answer would've been [-3, infinity))
A graph can be found here:
http://www.wolframalpha.com/input/?i=g%28x%29+%3D+4%5Ex+-+3