Please revise Completing the Square first...
Our aim is to get the equation into the form: (x − h)2 + (y − k)2 = r2
We complete the square on the x-related portion and on the y-related portion, at the same time.
Group the x parts together and the y parts togther:
Complete the square on each of the x and y parts.
`(x^2+8x+16)+(y^2+6y+9)` `=16+9` `=25`
This is now in the format we require and we can determine the center and radius of the circle.
So the centre of the circle is (-4, -3) and the radius is 5 units.
Note that the circle passes through (0, 0). This is logical, since (-4)2 + (-3)2 = (5)2
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