If the circumference of the circle x2+y2+8x+8y−b=0 is bisected by the circle x2+y2−2x+4y+a=0 then a+b=
-56
58
-58
54
Common chord is 10x+4y−b−a=0 is passes through (−4,−4)⇒−40−16=a+b⇒a+b=−56