Given system of circles is x2+y2+4x+7=0.....(i) 2(x2+y2)+3x+5y+9=0 or ‌‌x2+y2+‌
3
2
x+‌
5
2
y+‌
9
2
=0 .....(ii) and x2+y2+y=0......(iii) The radical centre can be obtained by solving the Eqs. (i), (ii) and (iii). On subtracting Eq. (ii) from Eq. (i), we get 4x−‌
3
2
x−‌
5
2
y+7−‌
9
2
=0 ⇒‌‌‌
5
2
x−‌
5
2
y+‌
5
2
=0 ⇒‌‌x−y+1=0....(iv) On subtracting Eq. (iii) from Eq. (i), we get 4x−y+7=0‌‌...(v) On solving Eqs. (iv) and (v), we get x=−2 and y=−1 Hence, radical centre is (−2,−1).