Find the indicated term.
-The fourth term of the expansion of $( s - t ) ^ { 12 }$
A) $- s ^ { 9 } t ^ { 3 }$
B) $- 220 s ^ { 9 } t ^ { 3 }$
C) $s ^ { 8 } t ^ { 4 }$
D) $495 s ^ { 8 } t ^ { 4 }$

Question

Quizplus · Accepted Answer

The fourth term of the expansion of $(s - t)^{12}$ can be found using the binomial theorem, which in general form is $(a + b)^n = \sum_{k=0}^{n} \binom{n}{k} a^{n-k}b^k$. For the fourth term (k=3), we use $\binom{12}{3} s^{12-3}t^3 = 220 s^9 t^3$, and since it's $(s - t)^{12}$, the sign is negative, making the correct answer $-220 s^9 t^3$.

Find the Indicated Term (s−t)12( s - t ) ^ { 12 }(s−t)12

Find the Indicated Term $( s - t ) ^ { 12 }$