Question: 2015 Fall Midterm - 8
What is the coefficient of $x^{81}y^{7}$ in the expansion of $(3x-17y)^{88}$?
(a)
$- {88 \choose 7} \cdot 3^7 \cdot 17^{81}$
(b)
${88 \choose 7} \cdot 3^7 \cdot 17^{81}$
(c)
$- {88 \choose 7} \cdot 3^{81} \cdot 17^7$
(d)
${88 \choose 7} \cdot 3^{81} \cdot 17^7$