Tween movement using AS

I want to move a movie clip from startx and starty to endx and endy using AS
but have it calculate the smallest distance and move the MC at a set speed accordingly so both X and Y stop in the right place at the same time.

in other words i want a small script to act like i have just tweened a MC
MC _X=0
MC _Y=0
Create Motion tween on frame 0
move on 50 frames
Create Motion tween on frame 50
set the _X from 50 to 100
set the _Y from 50 to 200

The movie clip moves to frame 50 but the _X moves at a slower speed than the Y because it has less distance to travel

can someone show me how this is done in AS
with a startX of 0 and a startY of 0
end X of 100 and an end Y of 200