Quote by amyparker30
x3 = 1/2a*t^2 + v*t v3 = a*t + v
3. The attempt at a solution
I just don't know how to get LEG3 x3, i know that v3 is zero because the rocket comes to a halt.

Hi amyparker30!
Since you know that v3 is zero, can you use the equation v3 = a*t + v to find the corresponding t?
Afterward you can fill in t in the equation x3 = 1/2a*t^2 + v*t.