What are some challenges for rational expressions?

Also on my previous question about why are polynomials important bobpursly can you expalin it to me towards what you ment about your responce because i still do not undertand...thanks when you get a chance.

Polynomials are important for computations. Most functions are not polynomials, but polynomials are the only things we can calculate. If a computer does some computations for some finite time, it can only have added up multiplied subtracted, divided a finite number of times...

To compute functions that are not polynomials we approximate them by polynomials.

good answer.