Write the equation of the circle in general form centered at (-2, -4) and that has a radius of 3 units.
Options
A
B
C
D
Answer & Analysis
Answer
B
Analysis
Question Analysis
The main focus is to convert the standard - form equation of a circle, based on the given center and radius, into the general form . This requires expanding the standard - form equation and simplifying the terms.
Key Concept Explanation
The standard form of a circle's equation is , where is the center of the circle and is the radius. The general form is . To get from standard to general form, we expand the squared binomials in the standard - form equation and combine like terms.
Step-by-Step Solution
1. Given the center and radius , the standard - form equation of the circle is .
2. Expand and using the formula :
and .
So the equation becomes .
3. Rearrange the terms to get the general form:
Combine the constant terms on the left - hand side: .
Calculate , resulting in the equation .
Option Analysis
A.
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