A specific expansion

Formula. $(2x-3)^4=\sum_{k=0}^{4}\binom{4}{k}(2x)^{4-k}(-3)^k$.

Expand.
- $k=0$: $\binom{4}{0}(2x)^4=16x^4$
- $k=1$: $\binom{4}{1}(2x)^3(-3)=-96x^3$
- $k=2$: $\binom{4}{2}(2x)^2(9)=216x^2$
- $k=3$: $\binom{4}{3}(2x)(-27)=-216x$
- $k=4$: $\binom{4}{4}(81)=81$

Conclusion. $(2x-3)^4=16x^4-96x^3+216x^2-216x+81$.