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Ch. 7 - Conic Sections
Blitzer - College Algebra 8th Edition
Blitzer8th EditionCollege AlgebraISBN: 9780136970514Not the one you use?Change textbook
Chapter 8, Problem 67

Find the solution set for each system by graphing both of the system's equations in the same rectangular coordinate system and finding points of intersection. Check all solutions in both equations. {x=(y+2)21(x2)2+(y+2)2=1\(\begin{cases}\)x = (y + 2)^2 - 1 \\(x - 2)^2 + (y + 2)^2 = 1\(\end{cases}\)

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Identify the two equations in the system: the first is \(x = (y + 2)^2 - 1\), which represents a parabola, and the second is \((x - 2)^2 + (y + 2)^2 = 1\), which represents a circle centered at \((2, -2)\) with radius 1.
To find the points of intersection, substitute the expression for \(x\) from the first equation into the second equation. This means replacing \(x\) in the circle's equation with \((y + 2)^2 - 1\).
After substitution, you will get an equation involving only \(y\): \((( (y + 2)^2 - 1 ) - 2)^2 + (y + 2)^2 = 1\). Simplify this equation step-by-step to form a polynomial in terms of \(y\).
Solve the resulting polynomial equation for \(y\). Each real solution for \(y\) corresponds to a point where the parabola and circle intersect. For each \(y\) value found, substitute back into the first equation \(x = (y + 2)^2 - 1\) to find the corresponding \(x\) coordinate.
Check each \((x, y)\) pair by substituting them into both original equations to verify that they satisfy both equations, confirming the points of intersection and thus the solution set of the system.

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Key Concepts

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

Graphing Equations in the Coordinate Plane

Graphing involves plotting points that satisfy an equation on the rectangular coordinate system. For nonlinear equations like parabolas and circles, understanding their shapes and key features helps in sketching accurate graphs. This visual representation is essential to identify where two graphs intersect.
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Graphs and Coordinates - Example

Systems of Equations and Intersection Points

A system of equations consists of two or more equations with common variables. The solution set is the set of points that satisfy all equations simultaneously, which correspond to the intersection points of their graphs. Finding these points graphically helps determine the solutions to the system.
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Checking Solutions by Substitution

After finding potential solutions from the graph, substituting these points back into the original equations verifies their validity. This step ensures that the intersection points truly satisfy both equations, confirming the solution set of the system.
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