Find the coefficient of `x^2` in `(3x + x^3)(x+(1)/(x))`

Find the coefficient of x^5 in (x + 3)^8

Find the coefficient of x^5 in (x+ 3)^6 .

Find the coefficient of x^6 y^3 in (x+2y)^9 .

Write: the coefficient of x^3 in 3x+x^2-6x^3+x^4

Find the coefficient of x^8 in the expansion of (x^2-1/x)^(10)

Coefficient of x^15 in (1+ x + x^3+ x^4)^n is

Find the coefficient of x^10 in the expansion of : (1+x+x^2+x^3 +.....+ x^10)^4 .

Find the coefficient of x^50 in the expression : (1 + x)^1000 + 2x(1 + x)^999 + 3x^2 (1 + x)^998 + ... + 1001 x^1000 .

Find the coefficient of x^5 in the expansion of (x+3)^6 is :