-- rational functions are quotients of polynomial functions

-- radical functions can be expressed as f(x) = p(x) / q(x), where p and q are polynomial functions and q(x) does not equal 0

-- the domain of a rational function is the set of all real numbers except the x-values that make the denominator zero

Example

f(x) = x^2 + 7x + 9 / x (x-2) (x+5)

p(x) is x^2 + 7x + 9

q(x) is x (x-2) (x+5)

-- the domain of the above example would be all real numbers excluding 0, 2, and -5