Chapter 4.7, Problem 6QC

Compare the growth rates of $f\left(x\right)=x^2$ and $g\left(x\right)=x^3$ as $x\to \infty$. Compare the growth rates of $f\left(x\right)=x^2$ and $g\left(x\right)=10x^2$ as $x\to \infty$.