Find the sum of first 51 terms of an A.P.whose second and third terms are 14 and 18 respectively

Find the sum of first 51 terms of an A.P.whose second and third terms

1.	Find the sum of first 51 terms of an A.P.whose second and third terms are 14 and 18 respectively
Answer» \xa0given,a2=14\xa0a3=18\xa0d=a3−a2=4\xa0a1=a2−d\xa0a1 =14-4a=10Sn=n/2(2a+(n-1)d)\xa0Sn=51/2(2*10+(51-1)4)\xa0Sn=5610