Find all $x$ such that both $2x$ and $3x-7$ are in the interval $(-1,12)$.
3x -7 in the required interval can only be (2 thru 6 1/3 )
then 2x to be in the interval can only be (-1/2 through 6) so the common factors are x = (2,6)
+819 
+36916 
