Elementary and Intermediate Algebra: Concepts & Applications (6th Edition)

Published by Pearson
ISBN 10: 0-32184-874-8
ISBN 13: 978-0-32184-874-1

Chapter 4 - Polynomials - 4.2 Negative Exponents and Scientific Notations - 4.2 Exercise Set - Page 245: 135



Work Step by Step

RECALL: (1) $a^{-m} = \dfrac{1}{a^m}$ (2) $a^1=a$ Use the rule above to obtain: $3^{-1}+4^{-1} \\=\dfrac{1}{3^1}+ \dfrac{1}{4^1} \\=\dfrac{1}{3} + \dfrac{1}{4}$ Make the fractions similar using their LCD of $12$ to obtain: $=\dfrac{1\color{blue}{(4)}}{3\color{blue}{(4)}} +\dfrac{1\color{blue}{(3)}}{4\color{blue}{(3)}} \\=\dfrac{4}{12}+\dfrac{3}{12}$ Add the numerators and copy/retain the denominator to obtain: $=\dfrac{4+3}{12} \\=\dfrac{7}{12}$
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