College Algebra 7th Edition

Published by Brooks Cole
ISBN 10: 1305115546
ISBN 13: 978-1-30511-554-5

Chapter 3, Polynomial and Rational Functions - Section 3.3 - Dividing Polynomials - 3.3 Exercises - Page 310: 70

Answer

$p(x)=2x^5+2x^4-18x^3-18x^2+40x+40$

Work Step by Step

Since $\sqrt{5}$ is a zero, to guarantee that the coefficients are integer it must be $-\sqrt{5}$ as another zero. Then, $p(x)=A(x+1)(x+2)(x-2)(x-\sqrt{5})(x+\sqrt{5})$ $p(x)=A(x+1)(x^2-4)(x^2-5)$ $p(x)=A(x+1)(x^4-9x^2+20)$ $p(x)=A(x^5+x^4-9x^3-9x^2+20x+20)$ $p(x)=Ax^5+Ax^4-9Ax^3-9Ax^2+20Ax+20A$ In order that the constant term is 40, it must be $20A=40\to A=2$. Now, we have $p(x)=2x^5+2x^4-18x^3-18x^2+40x+40$.
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.