Intermediate Algebra: Connecting Concepts through Application

Published by Brooks Cole
ISBN 10: 0-53449-636-9
ISBN 13: 978-0-53449-636-4

Chapter 1-6 - Cumulative Review: 6

Answer

$n = 0.984, -1.544$

Work Step by Step

$2.5n^{2} + 1.4n - 3.8 = 0$ $n = \frac{-(1.4)±\sqrt {(1.4)^{2}-4(2.5)(-3.8)}}{2(2.5)}$ $n = \frac{-1.4±\sqrt {1.96+38}}{5}$ $n = \frac{-1.4±\sqrt {39.96}}{5}$ $n = (0.98427...), (-1.54427...)$ $n = 0.984, -1.544$ Check: When $n = 0.984$ $2.5(0.984...)^{2} + 1.4(0.984...) - 3.8 \overset{?}{=} 0$ $2.5(0.96880...) + 1.4(0.984...) - 3.8 \overset{?}{=} 0$ $(2.42201...) + (1.3779...) - 3.8 \overset{?}{=} 0$ $(3.7999...) - 3.8 \overset{?}{=} 0$ $3.8 - 3.8 \overset{?}{=} 0$ $0 = 0$ When $n = -1.544$ $2.5(-1.544...)^{2} + 1.4(-1.544...) - 3.8 \overset{?}{=} 0$ $2.5(2.384795...) + (-2.1619...) - 3.8 \overset{?}{=} 0$ $(5.961...) + (-2.1619...) - 3.8 \overset{?}{=} 0$ $3.8- 3.8 \overset{?}{=} 0$ $0 = 0$
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