The coefficient of $x^{18}$ in $(ax^{4}-bx)^{9}$ after expansion is

E

Editor

Sep 18, 2022

The coefficient of $x^{18}$ in $(ax^{4}-bx)^{9}$ after expansion is

Difficulty: Easy

A:

84a^{3}b^{6}

B:

22a^{3}b^{6}

C:

27a^{4}b^{5}

D:

28a^{3}b^{6}

ID: 63273db9ca83163ac3a11877