Question

the coefficient of x3z4 in the expansion of (x???3z2)5 is

Answer 1

If we follow the binominal expansion then the terms will be taken up as

(x+y)^n = x^n + nc1 x^n-1y + ………… + y^n

nCk = n! / k! (n-k)!

for (x^3 z^4)

(x^ 3 z^4)^5 will fall

5C1 = 5! /1! (4!)

On opening it up you will get,

5 * 4! / 4!

Hence the answer will be 5