Question

Which of the following could be an example of a function with a range [a, ∞) and a range [b, ∞) where a > 0 and b >0?

Answer 1

The answers are 
 ƒ(x)=3√(x-b)+a  for [b, ∞)

proof
 ƒ(x)=3√(x-b)+a  for [b, ∞)
the domain is x-b>=0 implies x>=b it is the same of x is element of [b, ∞)