\chapter{Polynomial and rational functions} \section{Quadratic inequalities}
Check your understanding
Answer the questions in your own words. \begin{enumerate} \item When writing the solution of the quadratic inequality \((x-1)(x+4)\geq 0\) in interval notation, the numbers 1 and \(-4\) will appear in the solution. Do we need to use parentheses or brackets around them? \item When writing the solution of the quadratic inequality \(-(x+5)^2 < 0\) in interval notation, the number \(-5\) will appear in the solution. Do we need to use parentheses or brackets around it? \item What are the steps to solve the quadratic inequality \(a(x-3)(x+6)\leq 0\)? \item What are the steps to solve the quadratic inequality \(a(x-2)(x+2) > 0\)? \item Suppose that when we solve the quadratic equation \(2x^2 +bx +c=0\) we find no solutions. What is the solution of the quadratic inequality \(2x^2+bx+c> 0\)? \item Suppose that \(f(x)\) is a quadratic function with \(x=2\) and \(x=5\) as zeros. When we solve the inequality \(f(x)\geq 0\), could \((-\infty,2)\cup (5,\infty)\) be the solution? \item Suppose that \(f(x)\) is a quadratic function. What inequality do we need to solve to find the domain of \(\sqrt{f(x)}\)? \item Suppose that \(f(x)\) is a quadratic function. What inequality do we need to solve to find the domain of \(\displaystyle \frac{1}{\sqrt{f(x)}}\)? \item A quadratic function \(f(x)\) has no zeros, and \(f(0)=1\). What is the domain of \(\displaystyle \frac{1}{\sqrt{f(x)}}\)? \end{enumerate}
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