How do you graph #x^2+y^2-2x-4y-4=0#?

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Answer 1 · 2018-07-17T12:28:19

Please see the explanation below

The equation is

#x^2+y^2-2x-4y-4=0#

Complete the square

#x^2-2x+y^2-4y=4#

#x^2-2x+1+y^2-4y+4=4+1+4#

Factorise

#(x-1)^2+(y-2)^2=9=3^2#

This is the equation of a circle, center #C=(1,2)# and radius #r=3#

The graph is shown below

graph{(x^2+y^2-2x-4y-4)=0 [-8.065, 7.735, -2.18, 5.72]}