Follow the steps for graphing a rational function to graph the function Upper R left parenthesis x right parenthesis equals StartFraction x squared plus 13 x plus 40 Over x plus 8 End Fraction . 1 If​ needed, first write the given function as a single rational expression.​ Then, factor the numerator and denominator of​ R(x). Select the correct choice below​ and, if​ necessary, fill in the answer box to complete your choice.
A. ​R(x)equals enter your response here ​(Type your answer in factored form. Do not​ simplify.)
B. ​R(x) is already in factored form. Part 2 What is the domain of​ R(x)?
Select the correct choice below​ and, if​ necessary, fill in the answer box to complete your choice.
A. StartSet x|x greater than or equals nothing EndSet ​(Type an integer or a simplified​ fraction.)
B. StartSet x|x not equals nothing EndSet ​(Type an integer or a simplified fraction. Use a comma to separate answers as​ needed.)
C. StartSet x|x less than nothing EndSet ​(Type an integer or a simplified​ fraction.)
D. The domain is the set of all real numbers.