Consider the following statement:

1.The number of ways of arranging $m$ different things taken all at a time in which $p\le m$ perticular things are never together is $m!-\left(m-p+1\right)!p!$

2. A pack of 52 cards can be divided equally among four players in order in $\frac{52!}{{\left(13!\right)}^4}$ ways

Which of these is/are correct?

In how many ways the letters of word 'MACHINE' can be arranged so that vowels will always be together?

If the number of all possible permutations of the letters of the word $MATHEMATICS$ in which the repeated letters are not together is $90\left(X\right)$, then $X=$

How many numbers of four digits can be made by using the digits $3, 5, 6, 7,$ and $9$?  (Repetition of digits is not allowed)