Cocfficient of the term $x^{11}$ in the expansion of $\left(x^{4}-\frac{1}{x^{3}}\right)^{8}$ will be-

Solution: (c); Let $(r+1)^{\text {th }}$ term of the expansion is $x^{11}$

Then $(r+1)^{\text {th }}$ term is, ${ }^{8} C_{r}\left(x^{4}\right)^{8-r}(-1)^{r} \frac{1}{x^{3 r}}$

$\therefore 32-7 r=11 \therefore r=3 \therefore$ coefficient of $x^{11}={ }^{8} C_{3}(-1)^{3}=-56$