Finding t for Parametric Equations

[Whatupdoc]

Evaluate the line integral $$\int x^5*z*ds$$ where C is the line segment from (0,3,5) to (4,5,7)

so first thing i did was found the parametric equations
the parametric equations are:
x= 4t
y= 3+2t
z= 5+2t

how do i find out what t is? i totally forgot how to do that and i can't seem to find it in the book because it's so easy they don't bother to explain it. i can solve the problem if i know what t is, so help me if you can. thanks in advance

 

[Hurkyl]

Surely you can figure out what t is when, say, (x, y, z) = (0, 3, 5)?

 

[Whatupdoc]

lol ah thanks alot, i got it