\chapter{Polynomial and rational functions} \section{The Remainder and Factor Theorems}
Check your understanding
Answer the questions in your own words. \begin{enumerate} \item What does the Remainder Theorem say? \item We performed synthetic division on the polynomial \(f(x)\) and the final table looks like
\(2\) \(a\) \(b\) \(c\) \(d\) \(e\)
\(u\) \(v\) \(w\) \(x\)
\(y\) \(z\) \(s\) \(t\) \(3\)
What is \(f(2)\)? \item Let \(f(x)=3x^9-7x^5+8x^3-9x+8\). We divided \(f(x)\) by \(x+1\) using synthetic division and our final answer looks like
\(-1\) \(a\) \(b\) \(c\) \(d\) \(e\)
\(u\) \(v\) \(w\) \(x\)
\(y\) \(z\) \(s\) \(t\) \(r\)
What is \(r\)? \item Suppose \(f(x)=x^4-x^3+x^2-x+1\), and we want to find \(f(-9)\). Which method is faster: plug in \(x=-9\), or divide by \(x+9\) with synthetic division? \item Suppose \(f(x)=3x^{14}-2x^{12}-4x^7-2\), and we want to find the remainder of the division of \(f(x)\) by \(x-1\). Explain which method you would use, and why. \item What does the Factor Theorem say? \item We need to work with the polynomial \(f(x)=3x^8-7x^5+3x^2+8x+k\), and we can change \(k\) to be any number we like. Which number should \(k\) be to make sure that \(x+1\) is a factor of \(f(x)\)? \end{enumerate}
Back to Unit 2.5