Question

determinar centro e raio das circunferencias de equaçao x²+y²-2x-4y+1=0

Answer 1

$x^2+y^2-2x-4x+1=0\\ x^2+y^2-2x-4x=-1\\ (x^2-2x+1)+(y^2-4x+4)=-1+1+4\\ (x-1)^2+(y-2)^2=4\\ \\ C(1,2) \ e \ r=\sqrt4=2$