What is the expanded equation of a circle centered at (2, -3) with a radius of 5 units?
Answer and explanation
Correct answer: D. x^2 + y^2 - 4x + 6y - 12 = 0
- Step 1: (x - 2)^2 + (y + 3)^2 = 5^2. Step 2. x^2 - 4x + 4 + y^2 + 6y + 9 = 25. Step 3. x^2 + y^2 - 4x + 6y + 13 - 25 = 0 => x^2 + y^2 - 4x + 6y - 12 = 0. Answer: x^2 + y^2 - 4x + 6y - 12 = 0. Why not the others: +12 forgets subtracting 25 from 13.
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