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Ch. 3 - Polynomial and Rational Functions
Blitzer - College Algebra 8th Edition
Blitzer8th EditionCollege AlgebraISBN: 9780136970514Not the one you use?Change textbook
Chapter 4, Problem 87

Solve each inequality in Exercises 86–91 using a graphing utility. 2x2 + 5x - 3 ≤ 0

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Identify the inequality to solve: \(2x^{2} + 5x - 3 \leq 0\).
Rewrite the inequality as an equation to find critical points: \$2x^{2} + 5x - 3 = 0$.
Use the quadratic formula to solve for \(x\): \(x = \frac{-b \pm \sqrt{b^{2} - 4ac}}{2a}\), where \(a=2\), \(b=5\), and \(c=-3\).
Calculate the roots from the quadratic formula; these roots divide the number line into intervals to test for the inequality.
Use a graphing utility to plot \(y = 2x^{2} + 5x - 3\) and determine where the graph lies on or below the \(x\)-axis (i.e., where \(y \leq 0\)) to find the solution intervals.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Quadratic Inequalities

A quadratic inequality involves a quadratic expression set less than, greater than, or equal to zero. Solving it requires finding the range of x-values where the quadratic expression satisfies the inequality, often by analyzing the parabola's position relative to the x-axis.
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Graphing Quadratic Functions

Graphing a quadratic function y = ax² + bx + c produces a parabola. The graph helps visualize where the function is above or below the x-axis, which corresponds to positive or negative values of the quadratic expression, aiding in solving inequalities.
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Using Graphing Utilities

Graphing utilities, such as graphing calculators or software, allow quick plotting of functions to identify roots and intervals where inequalities hold. They provide a visual method to solve quadratic inequalities by showing where the graph lies relative to the x-axis.
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