Precalculus (6th Edition)

Published by Pearson
ISBN 10: 013421742X
ISBN 13: 978-0-13421-742-0

Chapter 2 - Graphs and Functions - 2.8 Function Operations and Composition - 2.8 Exercises - Page 286: 21

Answer

$\color{blue}{\bf{ 3x^2 - 4x + 3 }; \text{ domain } (-\infty,\infty) }$ $\color{blue}{\bf{ x^2 - 2x - 3 }; \text{ domain } (-\infty,\infty) }$ $\color{blue}{\bf{ 2x^4-5x^3+9x^2-9x }; \text{ domain } (-\infty,\infty) }$ $\color{blue}{\bf{ \dfrac{ 2x^2 - 3x }{ x^2 - x + 3 } }; \text{ domain } (-\infty,\infty) }$

Work Step by Step

We are given the two functions $\bf{f}$ and $\bf{g}$ $\bf{f(x) = 2x^2 - 3x }$ and $\bf{g(x) = x^2 - x + 3 }$ We are asked to find $\bf{( f+g )( x )}$ and its domain: $( 2x^2 - 3x )+( x^2 - x + 3 ) $ $2x^2+x^2 - 3x - x + 3 $ $\color{blue}{\bf{ 3x^2 - 4x + 3 }}$ $x$ can be any real number so its domain is: $\color{blue}{\bf{ (-\infty,\infty) }}$ We are asked to find $\bf{( f-g )( x )}$ and its domain: $( 2x^2 - 3x )-( x^2 - x + 3 )$ $2x^2 - 3x - x^2 + x - 3 $ $2x^2 - x^2 - 3x+ x - 3 $ $\color{blue}{\bf{ x^2 - 2x - 3 }}$ $x$ can be any real number so its domain is: $\color{blue}{\bf{ (-\infty,\infty) }}$ We are asked to find $\bf{( fg )( x )}$ and its domain: $( 2x^2 - 3x )( x^2 - x + 3 ) $ $2x^4-2x^3+6x^2-3x^3+3x^2-9x$ $\color{blue}{\bf{ 2x^4-5x^3+9x^2-9x }}$ $x$ can be any real number so its domain is: $\color{blue}{\bf{ (-\infty,\infty) }}$ We are asked to find $\bf{( \dfrac{f }{ g} )( x)}$ and its domain: $\color{blue}{\bf{ \dfrac{ 2x^2 - 3x }{ x^2 - x + 3 } }}$ $x$ can be any real number so its domain is: $\color{blue}{\bf{ (-\infty,\infty) }}$
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