Simplification of a pair of integers : simp2

### 2.8.6 Simplification of a pair of integers : `simp2`

`simp2` takes as argument two integers or a list of two integers which represent a fraction (for two polynomals see 2.28.6).
`simp2` returns the list of the numerator and the denominator of an irreducible representant of this fraction (i.e. after simplification).
Input :

`simp2(18,15)`

Output :

`[6,5]`

Input :

`simp2([42,12])`

Output :

`[7,2]`