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Question: 2019 Fall Midterm - 9

Author: Michiel Smid
What is the coefficient of $x^{24}y^{26}$ in the expansion of $(5x - 7y)^{50}$?
(a)
$- {50 \choose 26} \cdot 5^{24} \cdot 7^{26}$
(b)
${50 \choose 24} \cdot 5^{26} \cdot 7^{24}$
(c)
${50 \choose 26} \cdot 5^{24} \cdot 7^{26}$
(d)
$- {50 \choose 24} \cdot 5^{26} \cdot 7^{24}$