TS EAMCET 11-Sep-2020 Shift 1 Solved Paper

Let the roots of x3+ax2+bx+c=0 are α−1,α,α+1 as roots are in AP with common difference 1.
Now, sum of roots =3α=−a....(i)
Sum of product of roots taking two at a time
⇒‌‌3α2−1=b...(ii)
and product of roots =α(α2−1)=−c ....(iii)
From Eqs. (i), (ii) and (iii), we have
⇒9c=a(b−2)