The sum of all the coefficients of the terms in the expansion of `(x+y+z+w)^(6)` which contain `x` but not `y`, is

Options

A. `3^(6)`
B. `2^(6)`
C. `3^(6)-2^(6)`
D. none of these

Answer

C

Explanation

`(c )` The sum of coefficients of terms not containing `y=3^(6)` (putting `x=z=w=1` and `y=0`)
The sum of coefficients of term not containing both `x` and `y=2^(6)` (putting `z=w=1` and `x=y=0`)
So the required number `=3^(6)-2^(6)`