Statement-1 : If $S_n=\sum _{k=1}^n a_k=3n^2+2n-7$ for each $n$,then $a_1,a_2,a_3,\dots$are  in AP

Statement-2 : Sum to n terms of an A.P. is always of the form   $a{n}^2+bn$

 

 STATEMENT$-1$  is True, STATEMENT-2 is True; STATEMENT-2 is a correct explanation for STATEMENT-1

STATEMENT-1 is True, STATEMENT$-2$ is True; STATEMENT-2 is NOT a correct explanation for STATEMENT-1

 STATEMENT$-1$ is True, STATEMENT-2 is False

 STATEMENT-1 is False, STATEMENT$-2$ is True