How many ways are there to arrange the letters in the word GARDEN with vowels in alphabetical order

The coefficient of the middle term in the binomial expansion in powers of $$x$$ of $${\left( {1 + \alpha x} \right)^4}$$ and $${\left( {1 - \alpha x} \right)^6}$$ is the same if $$\alpha $$ equals

The number of ways of distributing 8 identical balls in 3 distinct boxes so that none of the boxes is empty is

The coefficient of $${x^n}$$ in expansion of $$\left( {1 + x} \right){\left( {1 - x} \right)^n}$$ is