Question 1171744
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{{{ x^2+y^2+2x-10y+30=0 }}}<br>

Observe the above for a moment, and re-write it as:
{{{ (x^2+2x+1)+(y^2-10y+25)+4=0 }}}<br>

Although you should by now notice there is going to be a problem, let's continue...
{{{  (x+1)^2 + (y-5)^2 + 4 = 0 }}}
{{{  (x+1)^2 + (y-5)^2 = -4 }}}

The form of a circle  centered at (h,k) with radius r, is 
{{{ (x-h)^2 + (y-k)^2 = r^2 }}} and we have {{{r^2 = -4 }}}.  
This circle has a radius of 2i  (2 times the imaginary unit). 
This is probably NOT what you wanted.  Check your post carefully
for accuracy and re-post with corrections or clarification.