Answer:
The domain is the set of values you put into the function.
The range is the set of values the function outputs.
Example problem:
Find the range of this function: y = 2x + 3, x > 0
The x > 0 part is the domain, so this means that only positive values of x can be inputted in the function.
If only positive values can be inputted in the function, then the range will be: y > 3