If the 11^( th ) term of an A.P.is - 21 and the sum of first 7 terms is -49 find the A.P

If the 11^( th ) term of an A.P.is - 21 and the sum of first 7 terms i

1.	If the 11^( th ) term of an A.P.is - 21 and the sum of first 7 terms is -49 find the A.P
Answer» 11th term=a+(11-1)d=(-21) a+10d=(-21) a=(-21-10d)Sum of first 7th term=7/2(2×a+(7-1)(d)=7(a+3d)=7(-21-10d+3d)=7(-21-7d)=49(-3-d)But,49(-3-d)=(-49) -3-d=(-1) d=(-2)a=-21-10(-2)=(-1)AP=(-1),(-3),(-5)....... 24