Algebra and Trigonometry 10th Edition

Published by Cengage Learning
ISBN 10: 9781337271172
ISBN 13: 978-1-33727-117-2

Chapter 1 - Review Exercises - Page 154: 85


Solutions: $x=2$ $x=-1$

Work Step by Step

Notice that: $-7x^3=x^3-8x^3$ $x^6-7x^3-8=0$ $x^6+x^3-8x^3-8=0$ $x^3(x^3+1)-8(x^3+1)=0$ $(x^3-8)(x^3+1)=0$ $x^3-8=0$ $x^3=8$ $x=\sqrt[3] 8=2$ or $x^3+1=0$ $x^3=-1$ $x=\sqrt[3] {-1}=-1$ Check the solutions: $x=2$: $2^6-7(2)^3-8=64-7(8)-8=64-56-8=0$ $x=-1$: $(-1)^6-7(-1)^3-8=1-7(-1)-8=1+7-8=0$
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.