Question

please help me
Explain what domain and range are,
Under what circumstances will a function have domain other than all real numbers?
Provide an example of a function whose domain is all real numbers and explain why. Your example can be either a graph or an equation.
Provide an example of a function whose domain isn't all real numbers and explain why. Your example can be either a graph or an equation.
Provide a third example to find the domain of.