Given that,

To find,
The domain of f(x).
Solution,
We have, 
To find domain,
The term under the square root must be positive or null as follows :

Adding 3 both sides

So, the domain is x-3>0
.
This question was once asked before so I will put it here.
The correct answer for the question that is being presented above is this one: "x = 2; a = 5; b = 3" A 5 inch tall bamboo shoot doubles in height every 3 days. If the equation y=ab^x, where x is the number of doubling periods, represents the height of the bamboo shoot.
Well what’s the base and what’s the height and then times then
-3x + 9 - 4 = x + 3 + 2x
-3x + 9 - 4 = 3x + 3
9 - 4 = 6x + 3
5 = 6x + 3
2 = 6x
1/3 = x