Question

Find the center and the radius and the center of the circle with the given equations:

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Answer 1

3. Center = (-1,3) Radius = 4

4. Center = (0,-7) Radius = 8

use completion of squares to find the solution, if you do not understand what this means, there is a great video on utube by the channel Prep Expert that explains finding the center of a circle based on an equation.

Answer 2

3. (-1 , 3) , 4

4. (0 , -7), 8

Explanation:

circle: (x-h)² + (y-k)² = r²

3. x²+2x+y²-6y-6 =0

(x²+2x+1) + (y²-6y+9) -16 =0

(x+1)² + (y-3)² = 4²

center(-1 , 3) radius: 4

4. x²+y²+14y-15=0

(x+0)² + (y²+14y+7²) - 64 = 0

(x+0)² + (y+7)² = 8²

center: (0 , -7) radius: 8