Question

An equation of a circle is x^2 + y^2 + 10x – 6y + 18 = 0. Show all your work in determining the center and radius of this circle. Explain the procedure used.

Answer 1

This requires Completing the Square for both x and y separately.

x^2 + 10x + _______ + y^2 - 6y + _____ = -18 + ______ + ______

Fill in the blanks!

Answer 2

Half of 10, and then squared.

x^2 + 10x + __25__ + y^2 - 6y + _____ = -18 + __25__ + ______

You do the 'y'-piece.

Answer 3

tkhunnys right

Answer 4

@tkhunny is right. You can also apply calculus if you've learned differential calculus.