Precalculus: Mathematics for Calculus, 7th Edition

Published by Brooks Cole
ISBN 10: 1305071751
ISBN 13: 978-1-30507-175-9

Chapter 1 - Section 1.7 - Modeling with Equations - 1.7 Exercises: 79


1) V=180feet$^{3}$ 2) 2 feet by 6 feet by 15 feet

Work Step by Step

1) Volume = (length)*(width)*(height) Therefore the volume is 180 feet$^{3}$ 2) x(x-4)(x+9)=180 $x^{3}+5x^{2}-36x=180$ $x^{3}+5x^{2}-36x-180=0$ $x^{2}(x+5)-36(x+5)=0$ $(x^{2}-36)(x+5)=0$ $(x+5)(x+6)(x-6)=0$ x+5=0; x=-5 x+6=0; x=-6 x-6=0; x=6 x=6 is the only positive answer Therefore, the box would be 2 feet by 6 feet by 15 feet.
Update this answer!

You can help us out by revising, improving and updating this answer.

Update this answer

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.