i get some ideas from another topic
https://www.physicsforums.com/showthread.php?t=274638"
i use the equation wut Dick offered X_p(s)-X_q(t)=u*W
then i get
(4,4,4)+t[-3,-6,-9] - (3,-1,5)+s[0,0,-5] = u[30,-15,0]<--cross product by deriction vectors
i solve it and get t=11/15...