knowing final v, time & distance, can i find the initial v?

Answer 1

Yes, assuming the velocity increased or decreased in a linear fashion (constant acceleration), it's easier than what eternaltr... did. (I couldn't follow what he did.)

Time & distance can give you the average velocity. Use the equation
s / t = (Vo + Vf) / 2

Answer 2

yep, you'd have to mess around with some variables though.

d=rt will give you the acceleration

so take that number and put it in this other formula to solve for Vi

vf^2=vi^2+at

where vf is final velocity, a is acceleration in which you solved for, vi is initial velocity, and t being time

so we mess around with the variables to solve for vi

√(vf^2-at)=vi

√=square root, and the (vf^2-at) is all under the square root

Answer 3

You need to know the acceleration also. So no you can't.