Question

Find the coefficient of
x^5 y^7

in the
expansion of (x-2y)^12

​

Answer 1

$\begin{array}{c | c }</p><p></p><p>&25 \\</p><p></p><p></p><p>\cline{2-2} 2 & 625 \\</p><p> </p><p>+2 &-4\:\:\:\:\: \\</p><p></p><p>\cline{1-2} 45 & 225 \\</p><p></p><p> +5 & -225 \\</p><p></p><p>\cline{1-2} 50 & 0</p><p></p><p></p><p>\end{array}$