Now if you understand the definition of range and domain it will be a lot simpler to answer.
Domain: The values that you can put into a function
Range: The values that the function spits out.
So the range here is from 25 to 64.
f(k)=k^2+2k+1, where f(k) is the range and k is the domain.
You will have to solve two equations for the boundary values, that is:
25=k^2+2k+1 and
64=k^2+2k+1
