If the circle x2+y2+4x+22y+l=0 bisects the circumference of the circle x2+y2−2x+8y−m=0 , then l+m is equal to
S1:x2+y2+4x+22y+l=0
S2:x2+y2–2x+8y–m=0
Since S1 bisects the circumference of S2, the common chord will be a diameter of S2
⟹ Common chord will pass through C2
Common chord: S1–S2=0
⟹6x+14y+l+m=0
It passes through C2(1,−4)
⟹l+m=−6(2)–14(4)=−6+56
l+m=50