Intermediate Algebra for College Students (7th Edition)

Published by Pearson
ISBN 10: 0-13417-894-7
ISBN 13: 978-0-13417-894-3

Chapter 5 - Section 5.4 - Factoring Trinomials - Exercise Set - Page 363: 131

Answer

$\{-16,-8,8,16\}$

Work Step by Step

We are given the trinomial: $$p(x)=3x^2+bx+5.$$ As the trinomial is a quadratic function, it can be factored if it has real root(s) $$\begin{align*} b^2-4(3)(5)&\geq 0\\ b^2-60&\geq 0. \end{align*}$$ So the trinomial can be factored for any real value of $b$ in the set $(-\infty,4\sqrt{15}]\cup[4\sqrt{15},\infty)$. $$\begin{align*} 3x^2+bx+5&=(3x+u)(x+v)\\ 3x^2+bx+5&=3x^2+(3v+u)x+uv\\ b&=3v+u\\ uv&=5\\ u=1,v=5\text{ or }u=-1,v=-5&\text{ or }u=5,v=1\text{ or }u=-5,v=-1\\ b=3(5)+(1)\text{ or }b=3(-5)+(-1)&\text{ or }b=3(1)+5\text{ or }b=3(-1)+(-5)\\ b=16\text{ or }b=-16&\text{ or }b=8\text{ or }b=-8. \end{align*}$$ All $4$ values are inside the domain. So the integer values of $b$ are $\{-16,-8,8,16\}$.
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.