Table of contents
- 0. Review of Algebra4h 16m
- 1. Equations & Inequalities3h 18m
- 2. Graphs of Equations43m
- 3. Functions2h 17m
- 4. Polynomial Functions1h 44m
- 5. Rational Functions1h 23m
- 6. Exponential & Logarithmic Functions2h 28m
- 7. Systems of Equations & Matrices4h 6m
- 8. Conic Sections2h 23m
- 9. Sequences, Series, & Induction1h 19m
- 10. Combinatorics & Probability1h 45m
1. Equations & Inequalities
Linear Inequalities
Problem 86b
Textbook Question
Solve each inequality in Exercises 86–91 using a graphing utility. x^2 + 3x - 10 > 0
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Identify the inequality to solve: x^2 + 3x - 10 > 0. This is a quadratic inequality.
Rewrite the inequality in standard form if necessary. In this case, it is already in the form ax^2 + bx + c > 0, where a = 1, b = 3, and c = -10.
Use a graphing utility to graph the quadratic equation y = x^2 + 3x - 10. Look for the x-values where the graph of the equation is above the x-axis, as these x-values will satisfy the inequality.
Identify the x-values where the graph intersects the x-axis. These points are the roots of the equation and can be found using the graphing utility. These points divide the x-axis into intervals.
Test each interval determined by the roots to see if the values in those intervals make the inequality true. Choose a test point from each interval, substitute it into the inequality, and check if the inequality holds. The intervals that satisfy the inequality are part of the solution set.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Inequalities
Inequalities express a relationship where one side is not equal to the other, often using symbols like '>', '<', '≥', or '≤'. In this case, the inequality x^2 + 3x - 10 > 0 indicates that we are looking for values of x that make the quadratic expression positive. Understanding how to manipulate and solve inequalities is crucial for finding the solution set.
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Quadratic Functions
A quadratic function is a polynomial function of degree two, typically expressed in the form f(x) = ax^2 + bx + c. The graph of a quadratic function is a parabola, which can open upwards or downwards depending on the sign of 'a'. In this problem, the quadratic x^2 + 3x - 10 will be analyzed to determine where it is greater than zero, which involves finding its roots and analyzing the intervals.
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Graphing Utility
A graphing utility is a software tool or calculator that allows users to visualize mathematical functions and inequalities. By graphing the quadratic function x^2 + 3x - 10, one can easily identify the regions where the function is above the x-axis, thus solving the inequality. Familiarity with using graphing utilities is essential for efficiently analyzing and interpreting the results of such problems.
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