The sum of all the coefficients in the binomial expansion of $(x^2 + x - 3)^{319}$ is

Find the coefficient of $x^5$ in $(1+x+x^2)^8$.

If the number of terms in the expansion of $(x - 2y + 3z)^n$ is $45$,then $n=$

If the coefficients of $x^2$ and $x^3$ are both zero in the expansion of the expression $(1 + ax + bx^2)(1 - 3x)^{15}$ in powers of $x$,then the ordered pair $(a, b)$ is equal to

The sum of the coefficients in the expansion of $(1+x+x^2)^n$ is

For natural numbers $m, n$,if $(1 - y)^m(1 + y)^n = 1 + a_1y + a_2y^2 + \ldots$ and $a_1 = a_2 = 10$,then $(m, n) = \_\_\_\_\_\_$.