Intermediate Algebra (6th Edition)

Published by Pearson
ISBN 10: 0321785045
ISBN 13: 978-0-32178-504-6

Chapter 8 - Section 8.3 - Solving Equations by Using Quadratic Methods - Exercise Set - Page 502: 59

Answer

55 mph to Tucson, 66 mph from Tucson

Work Step by Step

To Tucson: $330 = x*(330/x)$ From Tucson: $330 = (x+11)*(330/(x+11))$ $330/x = 1+ (330/(x+11))$ $330/x*(x)(x+11) = 1*(x)(x+11)+ (330/(x+11))*(x)(x+11)$ $330 *(x+11)=(x)(x+11) + 330*x$ $330x+3630 = x^2+11x+330x$ $330x+3630 = x^2+341x$ $330x+3630-330x-3630 = x^2+341x-330x-3630$ $0=x^2+11x-3630$ $0=(x-55)(x+66)$ $x-55=0$ $x=55$ $x+66=0$ $x=-66$ We want a speed, so $x\ne-66$. $x=55$ $x+11$ $55+11=66$
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