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# If the circle $x^2+y^2+8x-4y+c=0$ touches the circle $x^2 +y^2+2x+4y-11=0$ externally and cuts the circle $x^2+y^2-6x+8y+k=0$ orthogonally then $k=$

$\begin {array} {1 1} (a)\;59 & \quad (b)\;-59 \\ (c)\;19 & \quad (d)\;-19 \end {array}$

Can you answer this question?

(b) -59
answered Nov 7, 2013 by