If the sum of the coefficients in the expansion of (x - 2y + 3 z)n is 128, then the greatest coefficient in the expansion of(1 + x)n is

Sum of the coefficients in the expansion of(x−2y+3z)n is (1−2+3)n=2n         (put x=y=z=1 )  ∴ 2n=128⇒n=7Therefore, the greatest coefficient in the expansion of(1+x)7 is 7C3 or 7C4 because both are equal to 35.