use the binomial theorem to determine the coefficient of x^33 in the expansion of(1/4-2x^3)^17
The general term is $\displaystyle {17 \choose r} \left( \frac{1}{4} \right)^r (-2 x^3)^{17-r} = {17 \choose r} \left( \frac{1}{4} \right) (-2)^{17-r} x^{51 - 3r}$.
Now substitute the value of $\displaystyle r$ that satisfies $\displaystyle 51 - 3r = 33$ into $\displaystyle {17 \choose r} \left( \frac{1}{4} \right)^r (-2)^{17-r}$.