How do you find the center and radius of the circle #x^2 + y^2 – 2x -3 = 0#?

1 Answer
Alan P.
Sep 7, 2016

Center: #(1,0)#
Radius: #2#

Explanation:

Given
#color(white)("XXX")x^2+y^2-2x-3=0#

Converting into standard circle form:
#color(white)("XXX")(x^2-2x)+(y^2)=3#

#color(white)("XXX")(x^2-2x+1)+(y^2-0)=3+1#

#color(white)("XXX")(x-1)^2+(y-0)^2=2^2#

Which is the standard circle form with
#color(white)("XXX")#center #(1,0)#, and
#color(white)("XXX")#radius #2#

Here's the graph of the original equation for verification:
enter image source here

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