Let sn be the sum of the first n terms of an AP.if S2n =3n +14n2.then what is the common difference

Let sn be the sum of the first n terms of an AP.if S2n =3n +14n2.then

1.	Let sn be the sum of the first n terms of an AP.if S2n =3n +14n2.then what is the common difference
Answer» Yuuhhh Maybe -56 Kkkk