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
7. Systems of Equations & Matrices
Graphing Systems of Inequalities
Problem 21b
Textbook Question
In Exercises 1–26, graph each inequality. y≥x^2−9
![](/channels/images/assetPage/verifiedSolution.png)
1
Step 1: Identify the inequality to graph: \( y \geq x^2 - 9 \).
Step 2: Recognize that the boundary of the inequality is the parabola \( y = x^2 - 9 \).
Step 3: Graph the parabola \( y = x^2 - 9 \) as a solid line because the inequality is \( \geq \), indicating that points on the line are included.
Step 4: Determine which side of the parabola to shade. Since the inequality is \( y \geq x^2 - 9 \), shade the region above the parabola.
Step 5: Verify by selecting a test point not on the boundary, such as the origin (0,0). Substitute into the inequality: \( 0 \geq 0^2 - 9 \), which simplifies to \( 0 \geq -9 \), a true statement, confirming the correct region is shaded.
Recommended similar problem, with video answer:
![](/channels/images/assetPage/verifiedSolution.png)
This video solution was recommended by our tutors as helpful for the problem above
Video duration:
5mPlay a video:
Was this helpful?
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Inequalities
Inequalities are mathematical expressions that show the relationship between two values when they are not equal. They use symbols such as '≥' (greater than or equal to) and '≤' (less than or equal to) to indicate the direction of the relationship. Understanding how to interpret and graph inequalities is essential for visualizing solutions in a coordinate plane.
Recommended video:
Linear Inequalities
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 the coefficient 'a'. In the given inequality, y ≥ x^2 - 9, the quadratic function is y = x^2 - 9, which opens upwards and has its vertex at the point (0, -9).
Recommended video:
Solving Quadratic Equations Using The Quadratic Formula
Graphing Techniques
Graphing techniques involve plotting points and understanding the shape of functions to represent them visually on a coordinate plane. For inequalities, it is important to determine the boundary line (or curve) and then shade the appropriate region that satisfies the inequality. In this case, after graphing the parabola y = x^2 - 9, the area above or on the curve will be shaded to represent the solution set for y ≥ x^2 - 9.
Recommended video:
Guided course
Graphs and Coordinates - Example
Watch next
Master Linear Inequalities with a bite sized video explanation from Patrick Ford
Start learning