A rational expression is a fraction in which the numerator and denominator are polynomials and a complex rational expression is a fraction where the numerator and denominator are rational expressions.
For example, we can take the following rational expressions:
![\begin{gathered} f(x)=(x^2-9x+5)/(x+1) \\ g(x)=(x^3+2x)/(2x^2+8) \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/maybakzsq298veru6cxq8nx780fs8zpf0v.png)
Both f(x) and g(x) are polynomial functions, we can use f(x) as the numerator of a complex rational expression and g(x) as the denominator to get:
![((x^2-9x+5)/(x+1))/((x^3+2x)/(2x^2+8))](https://img.qammunity.org/2023/formulas/mathematics/college/uk2rhfavb9sifhs6djsfqofwizdhdo21w1.png)
Similarly, we can formulate 2 more complex rational expressions like this:
![\begin{gathered} \frac{\frac{x^2^{}+3}{x^3+2x-1}}{(2x-4x^2)/(x)} \\ \\ ((3)/(x-3))/((4x+4)/(2)) \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/djimjqs1y4hptmc1f36lyxe0x1xm04bmgq.png)