a. Prove that a polynomial function $y=P(x)$ is continuous at every number $x$. Follow these steps:
i. Use Properties 2 and 3 of continuous functions to establish that the function $g(x)=x^{n}$, where $n$ is a positive integer, is continuous everywhere.
ii. Use Properties 1 and 5 to show that $f(x)=c x^{n},$ where $c$ is a constant and $n$ is a positive integer, is continuous everywhere.
iii. Use Property 4 to complete the proof of the result.
b. Prove that a rational function $R(x)=p(x) / q(x)$ is continuous at every point $x$ where $q(x) \neq 0$.