Binomial theorem

1.(multiple answer possible) If the sum of the coefficients in the expansion of (2x+y-z)^n is 128, then the value of r for which the coefficient of x^r in the expansion of (1+x)^n is the greatest is
(A) 7 (B)3 (C)4 (D)5

1 Answers

1357
Manish Shankar ·

putting x=y=z=1 in first equation,

2n=128

so n=7

Now in (1+x)7, greatest terms are the middle terms

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