Coordinates

2:7   means the line can be divided into   2+7 = 9 segments

from   3 to -4   is    -7         2 out of 9 segments would be    -7 * 2/9 added to  3 = 13/9 = 1 4/9 = x

          6 to 3    is -3            2 out of 9 segments would be     -3 * 2/9 added to 6  = 5 1/3 = y

P  =   

( 3  +  (2/9) (-4 - 3)  ,   6  +  (2/9) ( 3 - 6)  )  =

(3  - 14/9  ,  6 -  6/9)  =

(  27/9 - 14/9 ,  18/3 - 2/3)  =

(13/9 , 16/3)