Question 864760
sphere with center (0,0,0) and radius r ⇒ x^2 + y^2 + z^ 2 = r^2. 
{{{2x^2+2y^2+2z^2-4x+1=0 }}}
2x^2+2y^2+2(z-2)^2 -4 + 1 =0 
 x^2 + y^2 + (z-2)^2 = 3/2 , r^2 = 3/2