Question 379772
{{{y^2 -2y= x^2 -4x + 4}}}
{{{y^2-2y+1=x^2-4x+4+1}}}
{{{(y-1)^2=(x-2)^2+1}}}
.
.
.
{{{drawing(300,300,-4,6,-4,6,grid(1), graph(300,300,-4,6,-4,6,0,1+sqrt((x-2)^2+1)),graph(300,300,-4,6,-4,6,0,1-sqrt((x-2)^2+1)))}}}