College Algebra 7th Edition

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

Chapter 3, Polynomial and Rational Functions - Chapter 3 Review - Exercises - Page 358: 93

Answer

$( -\infty, -1] \cup \left[ \frac{3}{2}, \infty\right)$

Work Step by Step

1. Express the inequality in the form $f(x)<0, f(x)>0, f(x)\leq 0$, or $f(x)\geq 0,$ where $f$ is a polynomial function. $2x^2\geq x+3$, $2x^2-x-3 \geq0$, $2x^2+2x-3x-3 \geq 0$, $2x(x+1)-3(x+1) \geq 0,$ $(2x-3)(x+1)\geq0,$ 2. Solve the equation $f(x)=0$. The real solutions are the boundary points. $(2x-3)(x+1)=0$ $x=-1$ or $x=\frac{3}{2}$ 3. Make a table or diagram: use the test values to make a table or diagram of the sign of each factor in each interval. 4. Test each interval's sign of $f(x)$ with a test value, $\begin{array}{llll} Intervals: & a=test.v. & f(a),signs & f(a) \geq 0 ? \\ & &(2a-3)(a+1)& \\ (-\infty, -1) & -2 & (-)(-)=(+) & T\\ (-1, \frac{3}{2}) & 0 & (-)(+)=(-) & F\\ (\frac{3}{2},\infty) & 2 & (+)(+)=(+) & T \end{array}$ 5. Write the solution set, selecting the interval or intervals that satisfy the given inequality. If the inequality involves $\leq$ or $\geq$, include the boundary points. Solution set: $( -\infty, -1] \cup \left[ \frac{3}{2}, \infty\right)$
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.