What is the Domain?
What is the Range?

[tex]f(x)=5x\\\\\text{The domain:}\ D=\{0,\ 1,\ 2,\ 3,\ 4,\ 5,\ 6\, ...\}=\text{Whole numbers}\\\\\text{The range:}\\\\f(0)=5(0)=0\\f(1)=5(1)=5\\f(2)=5(2)=10\\f(3)=5(3)=15\\f(4)=5(4)=20\\f(5)=5(5)=25\\\vdots\\R=\{0,\ 5,\ 10,\ 15,\ 20,\ 25,\ ...\}[/tex]