If the coefficients of $x$ and $x^2$ in $(1+x)^p(1-x)^q$ are 4 and -5 respectively, then $2 p+3 q$ is equal to

If $(20)^{19}+2(21)(20)^{18}+3(21)^2(20)^{17}+\ldots \ldots . .+20(21)^{19}=\mathrm{k}(20)^{19}$, then k is equal to $\_\_\_\_$ .

The absolute difference of the coefficients of $x^{10}$ and $x^7$ in the expansion of $\left\{2 x^2+\frac{1}{2 x}\right\}^{11}$ is equal to

If the coefficients of $x^7$ in $\left(a x^2+\frac{1}{2 b x}\right)^{11}$ and $x^{-7}$ in $\left(a x-\frac{1}{3 b x^2}\right)^{11}$ are equal, then

The coefficient of $x^5$ in the expansion of $\left(2 x^3-\frac{1}{3 x^2}\right)^5$

Let $\left(1+x+x^2\right)^{10}=a_0+a_1 x+a_2 x^2+\ldots+a_{20} x^{20}$. If $\left(a_1+a_3+a_5+\ldots+a_{19}\right)-11 a_2=121 k$, then $k$ is equal to $\_\_\_\_$

If $\sum_{r=0}^{10}\left(\frac{10^{r+1}-1}{10^r}\right) \cdot{ }^{11} C_{r+1}=\frac{\alpha^{11}-11^{11}}{10^{10}}$, then $\alpha$ is equal to :

If $1^2 \cdot\left({ }^{15} C_1\right)+2^2 \cdot\left({ }^{15} C_2\right)+3^2 \cdot\left({ }^{15} C_3\right)+\ldots+15^2 \cdot\left({ }^{15} C_{15}\right)=2^m \cdot 3^n \cdot 5^k$, where $\mathrm{m}, \mathrm{n}, \mathrm{k} \in \mathrm{N}$, then...

Let $\alpha$ be the constant term in the binomial expansion of $\left(\sqrt{x}-\frac{6}{x^{\frac{3}{2}}}\right)^n, n \leq 15$. If the sum of the Coefficients of the remaining terms...