If the roots of x³-13x²+kx-27=0 are in G.P., then k=

If $\frac{\mathrm{a}}{\mathrm{r}},\mathrm{a},\mathrm{ar}$ are the roots, then product of the roots is a³=27$\Rightarrow$a=3. Substitute x=3 in given equation since  is a root of the given equation. We get 27-13(9)+3k-27=0$\Rightarrow$3k=9(13)$\Rightarrow$k=39