Best way to Parametrize equation (quick 10 points, will vote asap)

line segment from (2,4,6) to (1,2,3)

i used x(t) = x1 +(x2-x1)t
y(t) = y2 +(y2-y1)t
z(t) = z2 +(z2-z1)t 0<=t<=1

This complicates my integration when I calculate Work for a given F

Now when i check solution, they parametrized the line segment by x(t) = t, y(t)=2t and z(t) = 3t

where 1<=t<=2

Please explain how to find the parametric equations (x=t, y =2t, z =3t)

Thanks

Note that the point P(2,4,6) is twice the point Q(1,2,3), so they simply let x = t, y = 2t, and z = 3t with 1 ≤ t ≤ 2

Yin